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"This definition is ''occasionally'' used in United Kingdom," So far as I'm concerned most people in the Uk above a certain age - let's say 45 - and many people younger still think in pints and gallons. There is a strong emotional attachment to Imperial measures. It's a lot more than occasional use - it's still engrained in the culture! Milk is still sold in pints 1 pint = 568ml) in all major supermarkets. I shall delete the "occasionally" unless I see convincing arguments no to. ] 23:41, 27 February 2007 (UTC)
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== Exchequer gallon (1091) ==
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"Exchequer (Henry VII, 1091, with rim)" sounds to me like it is claiming that size to have been used in 1091 under Henry VII of England.
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There's a problem with this, as the King of England in 1091 was William II. Henry VII was crowned in 1485. <span style="font-size: smaller;" class="autosigned">—Preceding ] comment added by ] (]) 17:54, 18 October 2008 (UTC)</span><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->
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== History ==
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"The metric definition of exactly 4.546 09 L was adopted shortly afterward."

I don't know that this has ever been officially adopted as the definition, anywhere. But it certainly is at least quasiofficial in at least the U.K. and Canada, a conventional conversion factor that has probably been at least declared to be good enough for legal purposes. Note that some lists of conversion factors such as of the U.K., do not claim to present any new definitions, but are rather merely compilations based on preexisting law. If you take them as official redefinitions, then the U.K. must have a weird definition of the hour, with a nautical mile defined as 1853 metres and a knot defined as 0.51477 metres per second (the actual legal definition of that nautical mile remains 6080 feet, notwithstanding the Units of Measurement Regulations 1995&mdash;note that the corresponding values for the international nautical mile are 1852 m and 0.51(4) m/s with the part in parentheses repeating, fours forever, no sevens to be found).

However, this statutory instrument may well be the one in which the 4.54609 litres became the quasi-official value for the United Kingdom. Before that, and going back into the 1970s at least, this value had been at least quasi-official in Canada, but the quasi-official value in the U.K. was different: 1 gal = 4.546092 litres. This distinction between a Canadian gallon and a U.K. gallon can still be found in many online lists of conversion factors, and in conversion programs which can be installed on computers.

Australia and New Zealand and other places may have similar lists of conversion factors in association with their metrication, but I don't know exact values, official status, or effective dates.

] 05:50, 31 Dec 2004 (UTC)

:NIST gives 4.54609 L/gal as the exact conversion factor for both the "UK and Canadian" imperial gallon(s) (Ref: Guide for the Use of the International System of Units (SI) - NIST Special Publication 811). The Canadian definition matches this and can be found at . Dunno about the UK. I've never seen the ...092 definition.
:] 15:32, 2004 Dec 31 (UTC)

::The Imperial gallon was redefined in 1963 to the values that Benoit determined in 1898. This replaced the 1824 definition that had been in force. The gallon can be determined from the definition as M.(b-a).l/(b*(w-a)), where M is 10 lb, b, w, a is the densities of brass, water and air in the act, and l is the conversion from mL to c.cm, ie l cu cm = 1 mL.
:: Putting l=1.000028 gives 1 gallon = 4.5460918785. Since l is variously this or 1.000027, it is prudent to round the gallon accordingly to 4.656092 or 4.54609, the latter is adopted in 1985 in the UK, and somewhat earlier elsewhere. ] 10:21, 18 September 2007 (UTC)
----
'The corn or dry gallon was used in the United States until recently for grain and other dry commodities.'
The use 'recently' isn't very accurate as it might have been recently when the article was written. What I could find about is was:

The words “The dry gallon shall contain two hundred and eighty-two cubic inches” have been omitted since this apparently conflicts with sec. 2304 of the General Statutes, which provides that “The weights and measures received from the United States * * * shall be the State standards,” as the National Government has never recognized or authorized the dry gallon mentioned above.
From the U. S. Dept. of Commerce, Bureau of Standards written in 1926. But that just says that it hasn't been officially recognized and not about it's usage.
] (]) 20:34, 11 June 2010 (UTC)

===U.K. 1963 redefinition===

The millilitre and the cubic centimetre were not the same in 1963. Were the densities in the 1963 redefinition specified in g/mL or in g/cm³? ] 11:47, 4 August 2005 (UTC)

----

Re the 1963 U.K. definition given here:

"In ], this definition was refined as the space occupied by 10 pounds of distilled water of density 0.998 859 ]/] weighed in air of density 0.001 217 g/mL against weights of density 8.136 g/mL."

Were these densities actually per millilitre, or were they per cubic centimetre? Note that the two were not the same thing in 1963. ] 05:55, 31 Dec 2004 (UTC)

:: For the gallon by this definition to yield both quoted values (4.54609 and 4.546092), the cm³ = 0.999 971 5 mL. This is a version of the Litre from 1900 to 1964. --] (]) 10:11, 18 January 2011 (UTC)


== Ambiguous gallons in 'mpg'. == == Ambiguous gallons in 'mpg'. ==
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::::The imperial gallon is still used when 'mpg' is quoted in Britain. As far as I know it is the dominant unit that British people use when discussing fuel efficiency even though fuel is sold in litres, not gallons. Manufacturers still quote it, for example Ford UK says the Focus does 8.7 L/100 km (32.5 mpg). Furthermore, in-car fuel efficiency displays quote 'mpg' and mean the imperial gallon. Many British readers assume that 'mpg' refers to the imperial gallon because they are not aware of any other gallon. I suspect that the same would apply in other countries. ]&nbsp;&nbsp;] 10:40, 21 Jun 2005 (UTC) ::::The imperial gallon is still used when 'mpg' is quoted in Britain. As far as I know it is the dominant unit that British people use when discussing fuel efficiency even though fuel is sold in litres, not gallons. Manufacturers still quote it, for example Ford UK says the Focus does 8.7 L/100 km (32.5 mpg). Furthermore, in-car fuel efficiency displays quote 'mpg' and mean the imperial gallon. Many British readers assume that 'mpg' refers to the imperial gallon because they are not aware of any other gallon. I suspect that the same would apply in other countries. ]&nbsp;&nbsp;] 10:40, 21 Jun 2005 (UTC)


: Are there any actual article examples where mpg is used and there is an ambiguity over which mpg is being referenced? I think it's safe to assume that if the article is about a Cadillac then it's US mpg, and if it's about an Aston Martin, then imperial mpg. But a Volkswagen or a Honda would be less obvious. Still, this entire discussion seems hypothetical. ] (]) 00:33, 5 April 2021 (UTC)
==Proposed WikiProject==
:: If mpg is used, ever, then it is ambiguous and should be converted to (eg) L/(100 km). ] (]) 08:55, 5 April 2021 (UTC)
Right now the content related to the various articles relating to measurement seems to be rather indifferently handled. This is not good, because at least 45 or so are of a great deal of importance to Misplaced Pages, and are even regarded as ]. On that basis, I am proposing a new project at ] to work with these articles, and the others that relate to the concepts of measurement. Any and all input in the proposed project, including indications of willingness to contribute to its work, would be greatly appreciated. Thank you for your attention. ] 21:04, 2 May 2007 (UTC)
::{{u|Firejuggler86}}, the {{t|convert}} template disambiguates them by rendering them as either mpg<sub>‑imp</sub> or mpg<sub>‑US</sub>. -- ] (]). 09:45, 5 April 2021 (UTC)

== Cleanup ==

I'm trying to clean up this article. I don't like having bullet points in the lead section but it's difficult to avoid here. Can anyone suggest a better layout? ] (]) 22:47, 26 February 2008 (UTC)
:OK, done it. ] (]) 09:06, 27 February 2008 (UTC)

== Gallons Used as measurement for fuel in Burma ==

I'd like to see some references that support that Burma actually uses gallons as a measurement for fuel. The two links provided are:
* "... the Government cut the ration of subsidized gasoline from six to four imperial gallons a week"
* "The government, which holds a monopoly on fuel sales and subsidizes them, raised prices of fuel from 1,500 kyats (US $1.16) to 3,000 kyats ($2.33) per imperial gallon for diesel and to 2,500 kyats ($1.94) for gasoline."
These only indicate that gallons are used by the reporters that were writing about the events in Burma. The articles do not even touch the subject of what units are used in Burma. The second article even states the amounts in both US customary and SI units: "A canister of natural gas containing 65 liters (17 gallons) was raised from 500 kyats (39 US cents) to 2,500 kyats ($1.94)."
The article also mentions US dollars. I hope you agree that these articles don't show that the USD is used in Burma as currency. ] (]) 18:15, 19 March 2008 (UTC)

:It's unlikely, though that US writers would write of "imperial gallons", a unit not used in the US, unless the units used for the ration were in fact imperial gallons. Note that the second article says imperial gallons for the gasoline/diesel rations even as it converts the 65-liter figure to US gallons (65 liters is 14.3 imperial gallons, 17.2 US gallons) - and the prices (in local currency) as shown are very round numbers, unexpected if it were a conversion to a different unit size. --] (]) 14:28, 7 July 2008 (UTC)

Aren't you assuming that US writers know that there is a difference between US and imperial gallons? How many Americans are aware there are different versions of the gallon? <span style="font-size: smaller;" class="autosigned">— Preceding ] comment added by ] (]) 12:53, 18 December 2011 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->

== Countries where this system is till in use ==

As far as I know, the only two countries that still use this form of measurement are the United States of America, and the United Kingdom (people aged late 40s even though the (old French) gallon no longer has legal status in the U.K. Is there any evidence supporting any other countries where this measurement is still officially used? (older generations in Canada talk of gallons, but in general no one really understands it when their elders talk crazy like that) --] (]) 10:58, 26 May 2008 (UTC)

Yeah, as a Canadian I can tell you that virtually nothing is sold by the gallon here anymore. If it's liquid, it's sold by the Liter or the Milliliter. In Canada, the official changeover from the Imperial system to the Metric system happened in the 1970s, under Prime Minister Trudeau. That was only about 30 years ago, so there's still plenty of people around who were only taught Imperial weights and measures and don't really understand Metric. You might still see fruits and vegetables sold by the pound, but it's more usual to see it sold by the Kilogram. ] (]) 17:52, 28 November 2010 (UTC)

: Go to any car dealer in Canada, and he'll quote you fuel consumption in miles per gallon, and those gallons will be imperial gallons. The glossy brochures will have both litres per hundred kilometres and miles per imperial gallon, but even the youngest car buyers will be comparing the MPG numbers. But you're right, nothing is actually sold by the gallon in Canada anymore. ] (]) 21:47, 29 November 2010 (UTC)

I may go to a car dealer once every ten years, but I drive on the road daily and purchase gas weekly. If other people's habits are similar they will have the same experience. Litres & kilometres are encountered frequently, miles and gallons very, very rarely. Those gallons in MPG are not measured nor are the distances in miles. Litres per 100 km result from direct measurements, MPG results only from a conversion. <span style="font-size: smaller;" class="autosigned">— Preceding ] comment added by ] (]) 16:58, 5 November 2011 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->

:The on-board computer in my car calculates the number of miles I have travelled based on wheel rotations, and calculates the number of gallons left in my tank from the average level. It then calculates both the instantaneous and the average fuel consumption in miles per gallon. If I chose, I could ask it to display the results in litres per 100 km, but it would still calculate the result by conversion, it would not measure either litres or kilometres. ] 21:43, 5 November 2011 (UTC)

Actually you don't know for sure whether the car "calculates" miles per gallon and converts that figure to litres per 100 km or the reverse. It is more likely the electronics and software are designed to do the actual measuring and calculating in more accurate metric units and when less accurate USC or imperial is selected it is a conversions you are seeing. I base this on the fact that all cars today, no matter where they come from are engineered, designed, manufactured and serviced using the metric system. <span style="font-size: smaller;" class="autosigned">— Preceding ] comment added by ] (]) 18:07, 12 February 2012 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->

:Yes, I do know that neither miles nor kilometres are directly measured. Both are calculated. Similarly, neither gallons not litres are marked on the fuel tank. The software converts the level reading to whatever units are required by the display. I agree that manufacturers nearly always use metric units in the manufacturing process.

The devices that do the measuring either produce a designed number of pulses per metre (or other SI unit) or a voltage where the sensor is calibrated to produce a particular voltage per metre (or other SI unit). If the default units are chosen to be those of the design units in SI, the number is directly displayed. If non-SI units are chosen, the "number" is passed through a conversion routine before being displayed. ] (]) 01:39, 21 February 2012 (UTC)

:No, the devices just produce a number of pulses. They are calibrated to either kilometres or miles. The number of pulses or the voltage needs to be converted to whichever unit is chosen for the display. ] 08:15, 21 February 2012 (UTC)

As I said the device is DESIGNED to produce a specific voltage or number of pulses per an SI unit and the SI unit is what is derived. A non-SI unit results from the SI unit passing through a software conversion routine. With a conversion routine you can easily and cheaply create any non-standard unit of questionable meaning and accuracy you want. ] (]) 14:32, 26 February 2012 (UTC)

:Are you claiming that rotations of a tyre (which is sold in '''inch''' radius measurements) are counted, then converted into a metric equivalent, then converted back into miles for the odometer? This sounds like an irrational fear of imperial units. Are modern engineers really so out of touch with traditional units? I agree that software can perform any conversion you wish, into any units you choose. I suspect that real (rational) engineers just calibrate the measuring device in whatever units it is designed to display. ] 17:16, 26 February 2012 (UTC)

The tyres on my car are sold in metric as are everyone else who owns a modern car. http://www.sizes.com/home/automobile_tires.htm If you have a car with a mechanical display it will be designed to display the units the display is showing by selecting the right gearing. If it is modern digital, it is designed to work in SI units as the base and other units are converted to from the measured SI unit. I happen to have a rational dislike for that which serves no useful purpose other than to waste money and resources. Educated professionals such as engineers tend to look down on those Luddites that cling to the past. Real engineers would select the proper gearing to display the units intended on older style mechanical displays that can't be switched to other units but on digital devices where there is a choice of units the primary units are SI and the "whatever units" are software conversions. It only works to calibrate the electronics to a base set of SI units and use software to convert to the rest. ] (]) 05:18, 4 March 2012 (UTC)

:The article to which you link confirms my claim that tyres are sold based on an imperial measurement (inches) in their most basic dimension. I don't doubt that engineers now actually manufacture tyres to some metric equivalent. <strike>I hope that you are not claiming that "real engineers" use the car's gearing to measure distance travelled, because this is clearly false.</strike> Odometer readings are based on wheel revolutions, and modern odometers use a pulse counting system. This is digital, so is neither metric nor imperial, but is logically closer to imperial because each pulse corresponds to a distance measured in inches based on the radius of the wheel. Your dislike of imperial seems to go beyond the rational, but I do agree with you that modern engineers would be happier if they could abolish all imperial units. ] 08:30, 4 March 2012 (UTC)

All aspects of the automobile are concepted, designed, engineered and manufactured in metric units with no though of pre-metric units in mind. Tyre circumferences are neither round in millimetres or inches due to the non-roundness of pi. The fact is the engineers design the measuring devices to produce a result in metric units and any other units required by law in certain countries is done by a software conversion to those units from the metric units. It is done no other way no matter how much you want it to be. ] (]) 14:18, 11 March 2012 (UTC)
What do the people who don't have on board computers do? Is your MPG USC or imperial? <span style="font-size: smaller;" class="autosigned">— Preceding ] comment added by ] (]) 13:00, 18 December 2011 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->

:They nearly all use miles per gallon, and it is the imperial gallon, of course, in the UK, even if the on-board computer is fitted in a car from an American manufacturer. ] 18:04, 16 January 2012 (UTC)

Do they actually bother to do a cumbersome calculation or just guess at a number out of thin air? <span style="font-size: smaller;" class="autosigned">— Preceding ] comment added by ] (]) 18:09, 12 February 2012 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->

:I can speak only from my own experience. I convert the annoying litre readout at the pump to a more meaningful (to me) gallon figure, and then I divide the mileage reading by the number of gallons. All British cars have a "mileometer" not a "kilometre-ometer" as a fitted odometer, and the official annual "MOT test" records the distance travelled by the vehicle in miles. The calculation to convert litres to gallons is no more cumbersome that having to convert miles to kilometers. Many years ago I used a pocket calculator for the conversion, but I now use a spreadsheet, and yes, I do bother to do the simple calculation. I've noticed a significant drop in my car's miles per gallon rate during the recent sub-zero temperatures (or should I say "sub-32-degrees Fahrenheit?) ] 08:24, 13 February 2012 (UTC)

The litre readout is not what is annoying it is the continued use of obsolete units on the roads. I would think if those units were so wonderful British road engineers would use them too, but behind the scenes they use metric. Even many of the signs are placed at metric distances and the non-metric displayed on the signs if often wrong. ] (]) 01:39, 21 February 2012 (UTC)

:I'm sorry you are annoyed by the use of yards and miles, but they cannot become obsolete whilst they are still in use. I agree with your point about the signs being inaccurate, but this is often because a suitable location may not be available at the exact distance. ] 08:21, 21 February 2012 (UTC)

They aren't actually in use, as they are just the results of someone's running a number through a calculator or taking a wild guess. The actual use is in metric, thus they are obsolete. The signs are designed to be placed at measured survey points in accurate rounded metric distances. As stated below, they intend for the signs to be at a precise 100 m (or other rounded metric unit) location. ] (]) 14:32, 26 February 2012 (UTC)

::Actually the road manuals specify the signs showing "100 yards" shall be placed "100 metres" from the subject - see , page 128. ] (]) 11:21, 21 February 2012 (UTC)

:::The regulations require such signs to be placed within a 10% accuracy, so as a metre is about 1.094 yards that is perfectly within tolerance. Would you expect them to be placed at exactly 91.44 metres?

A convenient loophole that allows them to place the signs by design at exactly 100 m and still claim what is on the sign is true. Even though it may say 100 YARDS, we know it is really 100 m. ] (]) 14:32, 26 February 2012 (UTC)

:68.105.199.216, I think British engineers have been working in metric for decades - not necessarily because they choose to, but because their employers stipulate that they ''have'' to. Luckily for the population though, they generally have no such pressures or diktats to comply with, and what we know is that where people have a free choice in the matter, they overwhelmingly choose imperial units over metric. -- ] (]). 19:43, 21 February 2012 (UTC)

Engineers choose to use metric, it is part of their training to be efficient in it. Once they use it and see its perfection they develop a loathing for non-SI. It is that simple. The BBC ran an article recently (http://www.bbc.co.uk/news/magazine-16245391). All the professionals who commented were pro-SI. Metric haters tend to be kept out of the professions or freely stay away because they know they will be "forced to" use SI. ] (]) 14:32, 26 February 2012 (UTC)

:Most of the signs where I live were placed long before engineers worked in metric units, and milestones are placed at almost exactly 1760 yard intervals. Telephones on motorways are at mile intervals with intermediate markers at intervals measured in yards. I expect that engineers who have only metric instruments have to do awkward conversions. There is nothing "imperfect" about yards and miles. They are an alternative system, not an inferior system. I'm happy with both imperial and metric systems, so I don't see why either has to exclude the other. ] 17:16, 26 February 2012 (UTC)

Almost exactly sounds like not exactly. Sounds to me like almost exactly 1760 yards is exactly 1600 m. I'm sure those yard/mile intervals are really some rounded metre value that you have convinced yourself is yards. Engineers who work only in SI units use only metric instruments and never are involved in conversions. Only those on the outside looking in do that. Pre-metric units have always had a history of large variances with the units. If they were perfect, educated professionals, scientists and the whole world would be using them, but due to their imperfection they are ignored except by those who hate the world for moving forward instead of clinging to the past. They aren't alternative and aren't even a system, just a mixed collection of units. The world only needs one true system, including out of date units only creates confusion, division and unnecessary costs to the national economy. Those who stick to one system progress while those fighting to have two or more are in decline.

BTW, the next time you are on a motorway look for the survey markers (http://en.wikipedia.org/Driver_location_signs?iframe) that are 100 m apart, marked in metric units and are used as emergency driver location signs. So when you call in an emergency from the road, such as with a mobile phone, you are giving metric information to the operator. ] (]) 05:18, 4 March 2012 (UTC)

:When I said "almost exactly", I meant "at a carefully measured distance of 1760 yards", definitely not 1600 metres (with actual placement not being possible to the nearest thou!) I'm puzzled by your concept of "perfection". As I said, I'm happy with both sets of units, and don't regard either system as "perfect", though I can understand engineers not wanting to convert between units, and thus placing modern markers at metric intervals, even though one interval has to be different to fit into the exact mile. What they are not capable of doing is changing the past, when markers were placed at mile intervals. ] 08:30, 4 March 2012 (UTC)

::Much as I would like everybody to read ] (I am the main contributor), I feel that this thread is digressing. Please see p108 document for a list of countries that sell fuel by the gallon (UK/US specified in the document). ] (]) 08:48, 4 March 2012 (UTC)

Martin, Your PDF is dated 2009. A number of countries in Africa, the Caribbean and Arab Emirates have changed to litre sales since. Thus your information is invalid and obsolete. I'm sure if you can provide a similar document for 2012 you will see the change. Relying on dated material, as in this case, can produce serious errors. ] (]) 14:18, 11 March 2012 (UTC)

:::Thanks for the signs link, Martin, I'd found it from 68.105's link just before you posted it here. I must do some measuring on the local motorway (built in the '60s before the metric takeover amongst engineers) to see what units are now used. I agree we are way off topic with the miles discussion. I think 68.105 and I will just have to agree to differ. ] 09:16, 4 March 2012 (UTC)

When roads are redesigned, relocated, maintained to a degree that the whole sign is replaced, the new sign is placed at a rounded measured distance in metres, not yards. Even if there are some remnant signs somewhere out there still with real yard locations, they will eventually in due time be relocated when their time for replacement comes. The fact is the trend is to continue to place distance signs at metric marker points and this will not cease. BTW, there was no metric takeover amongst engineers. It was a decision made to make it more simple and precise when working with numbers. If imperial was really precise and user friendly, the engineers would have stuck with it. They didn't because working in imperial is both a royal PIA and error prone.

Don't forget all of British official Ordinance Survey Maps are on a metric grid. Between the maps and road work, you have a harmonised system. We can agree to disagree, but both of us can't be right and I'm not wrong on this issue. ] (]) 14:18, 11 March 2012 (UTC)

== Nautical mile ==
It is peripheral to this page, but it may be worth noting that despite the provisions of the UK's Units of Measurement Regulations 1995, the International definition of a Nautical Mile is 1852m, and most UK legislation in which it is relevant includes this definition (such as in "The Merchant Shipping (Distress Signals and Prevention of Collisions) Regulations 1996, where it says "(3) In these Regulations... ... "mile" means a nautical mile of 1,852 metres")
] (]) 09:51, 2 June 2008 (UTC)

== Common usage of gallon/litre etc ==
In the UK, it is no longer true to say that "Milk is sold in pints in all major supermarkets": it depends on the supermarket and on the dairy: Sainsbury's, for instance, sell their own label fresh milk in multiples of 568ml, but their own label UHT milk and most branded milk in litres. (see www.sainsburys.com)
: Same situation in Tesco, Asda and Co-operative. Some supermarkets sell all milk in metric only quantities: Best One, Nisa, Aldi, Spar (to name just some). ] (]) 10:59, 20 July 2011 (UTC)

And whilst there has been resistance to the change to metric units, it is dying out, and it is now rare to see the price of fuel "per gallon" quoted by anyone other than those who are trying to make a political point.

The idea that "Many British readers assume that 'mpg' refers to the imperial gallon because they are not aware of any other gallon." is interesting, but given that 95% of the world is not the USA, perhaps it would be more generic to say "Many American readers assume that 'mpg' refers to the US gallon because they are not aware of any other gallon."
] (]) 09:51, 2 June 2008 (UTC)

I disagree with the first part of what you said, Pints can legally be used as a volume of sale (There was an attempted EU resolution that would have out lawed this) but more importantly, Pub measures of Beer and Cider are always in Pints or divisions there of. As to the use of Gallons in fuel, Fuel is always sold in litres but Fuel economy is almost always in mpg, thats in both the motoring press and normally the Official literature of the car companies.
I totally Agree with the second point though as what you sugest as the mistake is true and that it sugests that the US system of measures is more correct than the SI units that almost literally every other country uses.(] (]) 21:27, 30 July 2008 (UTC))

Not true pints are only legal for draught beer in pubs, but bottled beer is in litres. Consider this situation: you drink Guinness(*) down at your local pub. They don’t have Guinness on tap, so when you ask for a Guinness they take a 500 mL bottle out of the fridge (or a 500 mL can) and serve you with that. You’re used to it, and indeed plenty of the UK pub-going public are used to being served 500ml servings of beer if their pub doesn’t do their favourite on draught.

It is a legal requirement to use pints for milk, but only for milk delivered to your door. <span style="font-size: smaller;" class="autosigned">— Preceding ] comment added by ] (]) 17:04, 5 November 2011 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->

I totally agree with the US-centric point two paragraphs back ... and similarly, I think it is ridiculous to use the word "unofficial" in the opening paragraphs regarding the Imperial gallon. This leads to ambiguity at best, confusion at worst. It should be clarified that the Imperial gallon WAS once the official unit in the UK and it is still in common use among people over a certain age (45/50). ] (]) 20:47, 14 December 2009 (UTC)
: Except that "gallon" isn't in common usage amongst anyone in the UK except for fuel economy figures in MPG. Occasionally the tabloid press will have a headline saying "Petrol Now £X per Gallon, Shock Horror" (where X is usually an integer unless it's a *really* slow news day) but since no-one buys petrol in gallons and haven't since the 1980's, it's a meaningless rant. ] (]) 10:59, 20 July 2011 (UTC)
:: Well I use "gallon" commonly, Steve, but then perhaps I'm not "anyone"? ] 21:48, 5 November 2011 (UTC)

It all depends on what is meant by use. How many products are sold in gallon units? How many products contain the word gallon on them? Do by the word "use" are you implying that someone translates the quantities declared on a package in order to say gallons and claim it is used? Uttering the word gallon is not use. Use implies actual measurement. How much actual measurement is done with gallons compared to parroting the word? <span style="font-size: smaller;" class="autosigned">— Preceding ] comment added by ] (]) 18:18, 12 February 2012 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->

:As I mentioned above, large tanks for fish, water and fuel are still advertised by their gallon sizes, but I agree that the gallon sizes have been translated into metric equivalents for most products to comply with labelling requirements. ] 08:07, 13 February 2012 (UTC)

Or more than likely the other way around. They engineered and designed and manufactured to a metric size and then the number is converted into gallons for the advertizement. Thus the gallon is not actually used just parroted. ] (]) 01:29, 21 February 2012 (UTC)

:I think the former gallon sizes have probably been converted to metric measurements for modern manufacturing processes (we agree there), but the traditional gallon sizes are retained as accurately as possible in some cases. I also agree that these containers are probably in a shrinking minority. ] 16:50, 26 February 2012 (UTC)

==] Tagging==
This article talk page was automatically added with {{tl|WikiProject Food and drink}} banner as it falls under ] or ]. If you find this addition an error, Kindly undo the changes and update the inappropriate categories if needed. The bot was instructed to tagg these articles upon consenus from WikiProject Food and drink. You can find the related request for tagging ] . Maximum and careful attention was done to avoid any wrongly tagging any categories , but mistakes may happen... If you have concerns , please inform on the ] -- ] (]) 04:21, 4 July 2008 (UTC)

== weighing in air ==

"''the volume of 10 pounds of distilled water weighed in air with brass weights with the barometer standing at 30 inches of mercury and at a temperature of 62 °F.''" How substantial is the difference between this weight and that of the same mass of water weighed in a vacuum (or between this amount and exactly 10 lb of water ''as'' weighed in a vacuum)? I assume it is a greater mass (and hence greater volume) than it would be in a vacuum, since water is less dense than brass. --] (]) 00:23, 27 July 2008 (UTC) That is, the mass of water involved is more than 10lb, since it will take more water to balance the brass weights in air than it would in a vacuum. --] (]) 00:24, 27 July 2008 (UTC)

If weighed against brass then (Asuming the same temperature) the same amount of Brass would balance the same amount of water. Either way the Mass can't change unless you change the amout of water which defeats the whole object of weighing it. the air should only effect the resistance against the movement of the balance and at the same temperature and gravity the ame amount of water will take up the same volume.(] (]) 21:32, 30 July 2008 (UTC))
:It's to do with ]. Because the volumes of the water and brass aren't the same, the two items displace different weights of air and thus receive different uplift. The effect would be more marked if weighed in water, less if weighed in helium, non-existent if weighed in a vacuum. --] (]) 21:51, 30 July 2008 (UTC)

Right but I was wondering how significant it would be. --] (]) 23:26, 12 August 2008 (UTC)
:Very approximately 5 grams uplift on the gallon weighed in air, compared to weighed in a vacuum, when worked out on the back of an envelope here. --] (]) 06:00, 13 August 2008 (UTC)

: Using the data for the 4.54609 mL figure (ie the 1963 act), 10 lb of water in vacuum would be 4540.991 cc, rather than 4546.09 cc. This is because a gallon of water actually contains more than 10 lbs of water. It contains eg 70,075.134 grains of water. This will exactly match a weight of 70,000 grains of brass, when the 70,000 grains was set in vacuum. --] (]) 09:55, 16 January 2011 (UTC)

== Definition of US gallon ==

According to the US NIST Special Publication 811 a US gallon equals 3,785412 liter (L). To my knowledge no change was made to this definition.
--] (]) 16:49, 24 November 2008 (UTC)

I believe that this is true for most of the US, where a gallon is defined as having a volume of 231 cu in at a temperature of 60 degrees, but is not true for Hawaii which, since the 1970s, has legislated a gallon of 234 cu in to keep them from being shortchanged by the fact that they were, in fact, getting their gas at an average temperature of well over 60 degrees. <span style="font-size: smaller;" class="autosigned">—Preceding ] comment added by ] (]) 02:58, 21 October 2010 (UTC)</span><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

== Is there a symbol for gallon? ==

I couldn't find any symbol for gallon (like '''m''' for meter, '''s''' for second, in the ], or the common use '''L''' for liter), nor in the lead section of the article, nor in the Definitions section. In the tables of the ] article it seems to be '''gal''', but I don't know if this is official nor if it applies the same to the dry and imperial gallons too.

Could any of the main editors consider including the symbol/s (if some exist) in the lead section of the article (I believe it belongs there, see ]) and/or in the Definitions section?

Many thanks.
--] (]) 16:50, 21 March 2010 (UTC)

:Good point. I found "gal" in the 2012 edition of ''NIST Handbook 44'', Appendix C (''General Tables of Units of Measurement''), page C-5 (''Units of Liquid Volume''). It's available as a PDF file from . ] (]) 14:56, 21 February 2012 (UTC)

::Note that the symbol for gallon is "gal" (lower gase "g") and the symbol for the ] (a cgs unit of acceleration equal to {{nowrap|1 cm/s<sup>2</sup>}}) , short for Gallileo, is "Gal" (Upper case "g"). ] (]) 06:19, 27 February 2012 (UTC)

:::"Gal" is an abbreviation for gallon, not a symol as in the SI sense; as such, and applying the normal rules of English grammar, it ''can'' be capitalised. -- ] (]). 07:21, 27 February 2012 (UTC)

:In the Apothecary system, the symbol for gallon was C., the abbreviation was Cong., both short for congius. If you go back far enough, these symbols and abbreviations would have been used for gallons in general. It's just that doctors, lawyers, and apothecaries continued to use Latin a bit longer than other people. ] (]) 14:30, 27 February 2012 (UTC)

== Merge discussion ==

I propose that Gallons per minute and Million gallons per year be merged into this article. ] (]) 11:51, 8 August 2010 (UTC)

== Most Common ==

from the text "is equal to exactly 3.785411784 litres or about 0.133680555 cubic feet. This is the most common definition of a gallon in the United States."

I doubt it. I would say the most common definition of the gallon in the US goes along the lines of 2 cups in a pint, 2 pints in a quart, 4 quarts in a gallon. IMHO, no one in the US knows (or cares) how many liters are in a gallon. <span style="font-size: smaller;" class="autosigned">—Preceding ] comment added by ] (]) 04:30, 4 October 2010 (UTC)</span><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

: The US gallon is '''defined''' as 231 cubic inches. This converts to 3.78511784 L exactly, but that is a derived figure, not a definition. The relation in cu ft is 231/1728 = 0.133680555 5/9 cu ft, is likewise derived from the definitions. --] (]) 09:59, 16 January 2011 (UTC)

== Stupidity of Litres per 100 kilometres ==

Who was the dishonest snake-oil salesman who thought pushing this on the public was a great idea. So you want to know how far a litre of petrol takes you? Too bad, official figures make you work hard with mental division!

Kilometres per litre would have been SMART. I really am interested in finding out the history behind this epically moronic decision. The only thing I can think of is collusion between manufacturers to make it difficult for consumers to understand the fuel efficiency of their vehicles. <span style="font-size: smaller;" class="autosigned">—Preceding ] comment added by ] (]) 07:30, 13 October 2010 (UTC)</span><!-- Template:UnsignedIP --> <!--Autosigned by SineBot-->

:You might not know, but its very common in Europe, and most people find it hard to "understand" it the other way round like miles/gallon. This has nothing to do with stupidity. Anyone can get used to either way. Greetings from Germany ;) ] (]) 12:34, 29 April 2011 (UTC)

:"Stupidity"? It all depends on what you want to know. If you want to know how many litres of fuel you need to do a given journey (where the distance is known in km), then litres per 100km is a far more useful value than its reciprocal. I use it all the time, despite being in the UK, where fuel is sold by litres but the roadsigns are still in miles (and car odometers measure miles). In the UK, whichever fuel consumption figure you use, you have to do some arithmetic to get results since *no-one* uses "miles per litre" or "litres per 100 miles" or whatever other hybrid system you can dream up. ] (]) 10:49, 20 July 2011 (UTC)

== Hatnote ] ==

This leads to ], a character in a vampire fighting game whose alternative name seems to be "Garon". A national stereotype appears to have been applied as, within Japan, this evidently could be spelled "Gallon". I suggest that, this far removed from Jon himself, very few readers requiring the character would stumble upon this page. The hatnote in unnecessary. --] (]) 06:11, 3 September 2011 (UTC)
:OK, no dissent. Implementing. --] (]) 06:01, 6 September 2011 (UTC)

== What exactly is the legal status of the gallon in the UK? ==

The (old French) gallon introduced into Britain, no longer has legal status and it is no longer possible to buy liquid quantities in that unit. Some people may use them in conversation but may no longer be used in commercial transactions.
We have this sentence in the article: {{quote|On 1 January 2000, it ceased to be a legal unit of measure within the United Kingdom for economic, health, safety or administrative purposes.}}

I think this needs clarification, from secondary sources if necessary. I've added a {{tl|clarify}} template to signify this. To make it clear what this means, we need to know under what circumstances it is illegal to use "gallon" and under what circumstances it is legal. Examples: is it illegal to buy petrol by the gallon? Is it illegal for newspapers to write about the price of fuel per gallon? Is it illegal for councils to ask how many gallons capacity ones cesspool is? Is it illegal to advertise fuel efficiency as miles per gallon? Is it illegal to buy, use or sell containers of integer gallons capacity? Is it illegal to talk about a cow's productivity in terms of gallons per whatever? Is it illegal to sell (or wear) a ] in the UK? Can water authorities use gallons as a unit? It isn't clear at all. -- ] (]). 17:17, 25 November 2011 (UTC)

:The article quotes the law verbatim. It would be ] to try and interpret the law. If you really want to know, speak to (and pay) a lawyer. You will be lucky to get a reliable secondary source - the legal bit about the offical fuel consumption figures contains text something like "Consumption shall be displayed in litres per 100 km and to the extent permitted by EU directive 80/181/RRC, in miles per gallon)" - is the government is sitting on the fence.] (]) 18:13, 25 November 2011 (UTC)

::As it doesn't make sense as it stands, and you say there isn't much chance of clarifying it, then perhaps it should be deleted - what's the point of it being there as it is? -- ] (]). 18:48, 25 November 2011 (UTC)

::That it is text from the EC doesn't help. They're all primary sources which need interpretaion. Leave the {{tl|clarify}} template there for a while. If no-one else comes along who is able to help, then we'll have to consider removing the unfathomable information. -- ] (]). 19:04, 25 November 2011 (UTC)

:::I have idetnified a paper that interprets the meaning of the directive as far as teh US Government is concerned. I have given its reference and removed the "citation needed" flag. ] (]) 20:35, 25 November 2011 (UTC)

::::That U.S. document though is from a meeting with the EU. It merely states the EU ideal, rather than the current reality. We need some (sourced) interpretation of what the law actually means to the UK population. Are gallons actually currently illegal in any circumstances - the current statement in the article suggests that they are? Are gallons legal in any circumstances? Is the law enforced? Has anyone ever been prosecuted for using them? -- ] (]). 10:07, 26 November 2011 (UTC)

:None of the suggested uses mentioned by DeFacto is illegal, but, in some cases, the EU requires litres to be also mentioned in printing of at least equal size (e.g. when selling milk in plastic containers). The water company would have to sell water by the litre, or at least print the rate per litre on the bill. The whole EU regulation dispute is a minefield because legal interpretation depends on whom you ask. It's best if we just report the (obscure) legislation, then report how it is currently interpreted. ] 08:29, 26 November 2011 (UTC)

::We need to be clear about what is illegal and when, rather the vague allusion currently there that they are now completely illegal in all circumstances. -- ] (]). 10:13, 26 November 2011 (UTC)

:::I have found some more references. Are you happy? ] (]) 18:56, 26 November 2011 (UTC)

=== Examples of use ===
A cursory web search turns up tens of thousands of hits on the word "gallon", just on the UK government website. Are the government flouting the law on a huge scale, or are we misrepresenting the meaning of any law? Here's a random sample of national government uses dated 2011:
* - "...the fuel tanks still contained approximately 7 gallons of fuel ..."
* - "A spill of around 5000 gallons of oil..."
* - "Rock Farm Dairy Whole Milk – pergals 3 gallons"
* - "...for polluting a river with thousands of gallons of slurry..."
-- ] (]). 11:02, 26 November 2011 (UTC)

:I checked DeFacto's search. Going onto Google, I used the search string "Gallon site:.gov.uk". The first few entries were:
:*A four gallon milk churn in a museum
:*Something from an archive website
:*Had both gallons and litres as alternatives
:*ditto
:*The "Gallon of Water Trail" is the name
:*Had both gallons and litres as alternatives
:*Estate of the late Sylvia Gallon
:*Had both gallons and litres as alternatives
:*The "Gallon of Water Trail" is the name (again!)
:*10,000 gallon fuel tank planning application.
:The only entry worthy of investigation is the last one - I don't know anything about it, bu tif it was described a "10,000 gallon tank" in the brochure before 1-Jan-2010, the it will not fall foul of the regulations. Apart form that entry, all the other entries either had gallons and litres or were of historic interest only. ] (]) 14:31, 26 November 2011 (UTC)

::So 1 in 10 of your sample. That'd be more than 30,000 then in the full search result of 300,00 plus.
::<p>Did you look at the results I found, all from the 3,450 results that this search string gave me: "gallon 2011 site:.gov.uk"?
::<p>But, intersestingly, you are also applying a further filter to the results. So it's not: 'On 1 January 2000, it ceased to be a legal unit of measure within the United Kingdom for "for economic, public health, public safety or administrative purposes".', as it currently states in the article; it's more like "On 1 January 2000, it ceased to be a legal unit of measure for some limited uses within the United Kingdom for "for economic, public health, public safety or administrative purposes"." And why do you say in your comment above "...in the brochure before 1-Jan-2010, the it will not fall foul of the regulations", when the article states "On 1 January 2000, it ceased to be a legal unit of measure..."? We need to reword the statement for now then, until we find out more about it. -- ] (]). 16:47, 26 November 2011 (UTC)

:::Two points - firstly the gallon was in the first tranche of units of measure that ceased to be legal, so I have corrected the article - the date is nopw 1 October 1995. Had you taken the time to read the references rather than just whinging, you woudl have spotted that. Secondly, the EU directive was amended again and as from 1 January 2010 which is why I used that date. I am not going to discuss it any further, you can do a little of yur own legwork.

== Conversion to cubic inches ==
We seem to have some discrepancies in our conversions between litres and cubic inches. I'll read the article again before I make alterations, in case I've missed some historical variation, but the figures just don't tally as I currently read them.
This is the paragraph that seems to have discrepancies:
''"This works out at approximately 4.5460903 L <strike>(277.4416 cu in)</strike>. The metric definition of exactly 4.54609 cubic decimetres (also 4.54609 L after the litre was redefined in 1964, ≈ 277.419433 cu in) was adopted shortly afterwards in Canada; for several years, the conventional value of 4.546092 L was used in the United Kingdom, until the Canadian convention was adopted in 1985."'' Perhaps it is the redefinition that I'm getting confused over? ] 08:29, 26 November 2011 (UTC)
: ... ''(later)'' ... I've altered one figure because I can't see how it was calculated. If it was based on an old metric value, please revert and add the explanation. ] 18:51, 28 November 2011 (UTC)

== Revocation of 28 November 2011 ==

I have revoked DeFacto's changes tp this artcile because:
#He replaced the word "legal" with the word "primary". The word "legal" appears in the phrase of Article 1 of the EU directive.
#He reworded the implications of the EU directive. The EU directive affected many aspects of life - LACROS only commented on those that affect them (trade), hence the wording "amongst other things". Removing that wording changes the meaning of the sentence. Health issues, for example, although mentioned in the dircetive, fall outside LACROS' remit, so LACROS will not comment on them.
] (]) 13:01, 28 November 2011 (UTC)

:The word "legal" is anbiguous in the phrase "the gallon ceased to be a legal unit of measure within the United Kingdom", so needs clarifying. As we have seen in discussions above above, gallon ''is'' a legal unit of measure - i.e. its use is not illegal in most contexts. For this reason the phrase needs clarifying. So far, all that we've got RS for, is that the gallon cannot be used as the primary measure for trading, although it is perfectly legal, apparently, as a secondary (supplementary) unit. If there are other meanings please provide RS for them too. -- ] (]). 13:28, 28 November 2011 (UTC)

::No one said that there are no RS to explain the term further. You are welcome to look for them yourself. ] (]) 16:25, 28 November 2011 (UTC)

:::The statement therefore remains ambiguous, so I've added the {{tl|ambiguous}} template to it. When we've clarified in what way the gallon is no longer legal we can consider removing the template - but surely not until then. -- ] (]). 16:48, 28 November 2011 (UTC)

::::The statement is certainly ambiguous, and I don't think an outdated interpretation by an American website belongs here. The legislation specifically modified previous legislation (hence the "legal") where quantities had been specified in Imperial units. It also said, in the explanation, that its intention was the "phasing out of the use, for economic, public health, public safety or administrative purposes, of imperial units of measurement", but paragraph 5.—(1) stated "Nothing in these Regulations shall apply in relation to any supplementary indication". The gallon is not only still legal, but is still used (optionally) as a supplementary unit in the UK, though the volume in gallons can be printed no larger than the equivalent metric unit. These websites might be useful: , , ] 19:20, 28 November 2011 (UTC)

:::::A few points from Dbfir's comments:
:::::*The EU directive appears to have extended the applicablity of the EU directive to all matters covered by the "internal market", but the UK government has not passed any legislation to cover that, nor am I aware of any court ruling to clarify what was meant.
:::::*I think that Dbfirs really meant "For purposes of ...., the gallon is legal only as a supplementary unit ...". On the other hand, if we describe the October 1995 situation we will not be indulging in any WP:OR which is why I have introduced the words "amongst others".
:::::] (]) 21:01, 28 November 2011 (UTC)

::::::The correct place to discuss the EU directive is at ], not here. In my view all the double quotes, caveats etc should be removed and relaced by a Wikilink to ''Metrication in the United Kingdom''. If we don't do this, we will have pseudo-copies of the same discussion in every artcile connectged with a unit of measure. In my view, that is a very silly hting to do. Moreover, if everything is centralised, then (hopefully) the full story will emerge, and if sublte changes emerge, they need only be added in one place. ] (]) 20:53, 28 November 2011 (UTC)

:::::::EU directives do not constitute British law, of course. There have been numerous British regulations since 1995, and all of them can be challenged by any British MP. I agree that the whole argument would be better moved to the general article. ] 22:49, 28 November 2011 (UTC)

::::::::On the contrary - under the European Communities Act 1972, EU directives are part of UK law, or more corerctly, the UK courts are obliged to honour them. ] (]) 08:10, 29 November 2011 (UTC)

:::::::::That's not the same as law. The directives are actually implemented in UK regulations which have the effect of law unless and until they are challenged by the British parliament. ] 08:43, 29 November 2011 (UTC)

:::::Dbfirs, yes, I agree that the U.S. meeting report adds nothing. We need to clarify the prose in this article to give a true picture of the status of the gallon. To say that it has "ceased to be a legal unit of measure" is grossly misleading without adding the actual meaning and context. It could leave the impression that it is somehow a criminal act to use or refer to gallons in the UK - which is, of course, nonsense. -- ] (]). 12:52, 29 November 2011 (UTC)

::::::I don't know where you picked that up from. Paragraph 3 of The makes no such provision. If you read ] you can see a bit more about EU directives. If the directive can be implemented without intervention by the UK Government, then, by virtue of the 1972 Act, itis automatically part of UK law. If it requires UK Governemnt intervention, the the UK government can required to make good any damages caused by its neglect (See ]).

::::::Anyway, this is well outside the scope of the current article. I believe it sufficient in this case to merely quote the basics of the EU directive and to leave discussion in the artcile ].

::::::I think that DeFacto is confused about what constitutes a "criminal acts". There are many branches of law - criminal law, family law, contract law, law of tort, commercial law, administrative law just to mention a few - the only common thing concerning all of these is that the courts are competant to pass judgement should they be asked to do so and contravenign a legal requirement only constitutes a "criminal act" if there is a penalty payable to the state fo rdoing so. I suggest that you read the article ] for a fuller understanding of the subject. ] (]) 13:10, 29 November 2011 (UTC)

:::::::Martinvl,
:::::::#You don't know where I picked up ''what'' from?
:::::::#The phrase that needs clarifying (or deleting) is: "the gallon ceased to be a legal unit of measure within the United Kingdom". that most certainly ''is'' within the scope of this article.
:::::::#This isn't about ''my'' understanding of how the law works, and no, I'm not confused about what constitutes a criminal act. What this is about is the poor and ambiguous phrasing in the article that may lead readers of this article to be left with the wrong impression as to the legal status of the gallon. That's why I've raised this issue here.
:::::::-- ] (]). 13:28, 29 November 2011 (UTC)

{{unindent}}
#You don't know where I picked up ''what'' from? - I was unclear here - I was refering to Dbfir's comments about Parliament.
#That phrase "the gallon ceased to be a legal unit of measure within the United Kingdom" must absolutely remain in place. As long as it is properly referenced, readers who need to know that about these things can seek proper legal advice.
#If you are concerned that readers might get the wrong idea, then we need to be clear that the one aspect of life that we cited is but one of many. If they have any concerns they should seek legal advice, not rely on Misplaced Pages. It woudl be wrong of us not to draw to attention that there were changes (some specified, others unspecified) regardign the use of the gallon on 1 October 1995.
] (]) 14:44, 29 November 2011 (UTC)

:I'll stick to 2 & 3 then. ''If'' we can clarify the phrase, ''then'' it can stay. Our job is to provide clear secondary source interpretation, not to obfuscate the issue with verbatim and unclarified quotes from legislation primary sources. -- ] (]). 15:06, 29 November 2011 (UTC)

:: ... (''"just to explain what I picked up"''). I got the impression from British MPs and from the British Government website that only the British parliament can make law that affects British people. I agree that this principle has been muddied slightly, but it seems to be mainly confirmed in the Misplaced Pages articles I found following Martin's links.

::e.g. ''"Directives are usually incapable of being horizontally directly effective due to the fact that they are only enforceable against the state."''

:: ''"The horizontal direct effect of Directives is a contentious issue amongst law makers of the European Community, numerous Advocate Generals have supported the case for establishing horizontal direct effect, however it is still currently unable to confer such rights."''

:: ''"Unlike Treaty provisions and regulations, directives cannot have horizontal effect (against another private individual or company), as this is adjudged contrary to the principles of equality (see Marshall v Southampton and South West Hampshire AHA (1986))."''

:: The statement presently in our article gives a different impression (the way I read it), and there is certainly no law that prevents people in the UK from using the gallon for most purposes, just that metric units of volume must also be given in trade, and that metric units must be used in certain documents. ] 16:50, 29 November 2011 (UTC)

:::I've just summarised, in a nutshell, the status of the gallon in the article with reference to the appropriate UK law. How does that look? -- ] (]). 17:07, 29 November 2011 (UTC)

::::I think that is a clearer way to express the complex situation. I'm guessing that the only gallon legislation that the regulation modified was that on the wholesale supply of milk and wholesale & retail fuel, but there could be other laws. It would be better if we could cite a recent reliable British source on the interpretation, but I haven't found one yet. summarises the situation, but is not quite what I was looking for. It does have the sentence: ''"EU Directives are not laws in themselves. Rather they are instructions to the Member States, requiring them to amend their domestic legislation to bring it into conformity with the provisions of the Directive."'' ] 17:56, 29 November 2011 (UTC)

:::::Interesting, but that website is that of an anti-imperial units pressure group, and isn't a ]. -- ] (]). 18:26, 29 November 2011 (UTC)

::::::Yes, it's not impartial, I agree, but it was useful to use an anti-imperial site to make a pro-imperial point. I'm still looking for a good reference for a Misplaced Pages cite. ] 22:28, 29 November 2011 (UTC)

== Supplementary vs Secondary ==

The EU directive and hence the UK legislation does not define the terms "primary" and "secondary" in respect of units of measure, but does mention "supplementary untis of measure". Introducing the terms "primary" and "secondary" into the article is therefore taking a novel position which is ]. I have reinstated an earlier version as this does not include the words "primary" and "secondary". I have also included a reference to the use of the gallon as a supplementary unit of measure. ] (]) 12:51, 30 November 2011 (UTC)

:The cited document "" uses the terms "primary" and "secondary" when explaining how units from the two systems can be used side-by-side. Anyway, the use of those terms helps clarify the meaning of the legislation - we are allowed to paraphrase and explain details in our own words. That's just common sense, and certainly not OR. -- ] (]). 13:13, 30 November 2011 (UTC)

::As you rightly mentioned the DTI article uses the words "primary" and "secondary" in a special context - to differentiate between two units of measure that have ''already'' been associated with each other. However, the DTI document only uses the word "secondary" once in respect of units of measure, but uses the word "supplementary" a number of times. In normal English usage, a "secondary" item can stand alone - for example a "secondary school". Furthermore, the word "primary" is not used anywhere other than in the DTI document in the context of a "primary - secondary pair". For that reason we should use the words "primary" and "secondary" with great care because the legislation is quite clear - supplementry units must not be used in a stand-alone context. <small><span class="autosigned">— Preceding ] comment added by ] (] • ]) 14:38:13, 30 November 2011 (UTC)</span></small><!-- Template:Unsigned -->

I see the EU/UK content is being churned again. The idea of the article is to make it clear, not to keep obfuscating the issue. Neither the EU directives nor UK law has outlawed the use of gallon as a unit of measure per-se. All that the regulations have done is define metric units as the primary units which ''must'' be used in certain limited situations. None of which stop anyone from using gallons in much the same way as they always have done - the only proviso being that metric units must also be given (with no less than equal prominence) for certain activites to do with official government business and official documents and trading by volume. Why the apparent obsessive desire to prevent this being made very clear? -- ] (]). 14:31, 1 December 2011 (UTC)

:I have asked the OR noticeboard for advice. (]). ] (]) 16:21, 1 December 2011 (UTC)

::The references use the words "primary" and "supplementary". Are these not acceptable? ] 16:41, 1 December 2011 (UTC)

:::@Dbfirs: One reference uses the words "primary" and "secondary" once - in respect of "indicators", not "units". That same document uses the word "supplementary" half a dozen times. ] (]) 18:34, 1 December 2011 (UTC)

::::Martinvl, it's all semantics. Secondary or supplementary doesn't make too much difference to the meaning - does it? -- ] (]). 18:59, 1 December 2011 (UTC)

:::::It is not just a matter of semantics - it is a matter of clarity. Is a "derived unit" a "secondary unit"? Possibly or possibly not. Do you have any views? ] (]) 19:02, 1 December 2011 (UTC)

::::::As you may realise, context is essential to be able to disambiguate many, many words in the English language. -- ] (]). 19:25, 1 December 2011 (UTC)

::Martinvl, I take it from that then that you are trying to get support to obfuscate the reality of the regulations then, rather than cooperate here with other editors and attempt to agree a clearer wording. Why? -- ] (]). 16:49, 1 December 2011 (UTC)

:::If definitve wording exists, why complicate matters by using alternative wording that could be misconstrued? BTW, you still have not answered my question whether or not a "derived unit" is a "secondary unit"? ] (]) 20:41, 1 December 2011 (UTC)

::::Martinvl, what are you complaining about - the current text uses the word "supplementary" twice and "secondary" just once? And it only uses "secondary" as a reinforcement to "supplementary" in the phrase "...the gallon could still be used - but only as a supplementary or secondary unit.". Why reduce the clarity by eliminating one of the words?
::::<p>And what has whether a "derived unit" is a "secondary unit" got to do with it? The BIPM certainly don't call them that in the SI brochure. -- ] (]). 22:14, 1 December 2011 (UTC)

:::::DeFacto - did you actuallteh DTI reference? If you did, you woudl have realised that I ignored the instance of the word "secondary" when it was applied to "secondary legislation" - the terms "primary legislation" and "secondary legislation" are well understood in the British legal system. I don't know where you looked, but the BIPM certianly uses the word "derived" in its brochure. Why don't you look up s]? Using your logic, we could call a ] a "secondry unit" and ]s, ]s and ]s "primary units" even though the BIPM brochure uses the terms "derived units'' and "]s". If we did that, both the gallon and the watt could be deemed "secondary units" - clearly the EU are happy for the watt to be used but not the gallon. ] (]) 08:21, 2 December 2011 (UTC)

::::::Martinvl, your response is bizarre. Did you actually read your own question to me? The one I was answering - this one: '...you still have not answered my question whether or not a "derived unit" is a "secondary unit"'.
::::::Read it again, then read my reply - this one: "The BIPM certainly don't call them that in the SI brochure." "Them" being "derived units" and "that" being "secondary units" (if that much isn't blatantly obvious to you).
::::::Now read your follow-up - this bit: "I don't know where you looked, but the BIPM certianly uses the word "derived" in its brochure". I know what a derived unit is and I know that they are described in the SI brochure - but that wasn't what you asked. You asked whether a "derived unit" is a "secondary unit". I replied that it (a "derived unit") isn't described as such (as a "secondary unit") in the SI brochure.
::::::The rest of your reply, being based on the false and illogical premise, is therefore nonsense.
::::::Are we clear now? -- ] (]). 09:00, 2 December 2011 (UTC)

== Usage in the United Kingdom ==

To the best of my knowledge, the gallon ceased to be a legal unit of measurement in the United Kingdom on the first of January, 2000 (http://www.legislation.gov.uk/uksi/1995/1804/contents/made). Could anyone please clarify as the article says the gallon is "used" in the United Kingdom. ] (]) 03:14, 3 February 2012 (UTC)

:Well, not all of us obey European directives! In fact, the regulation to which you link does not ban the use of the gallon, but states that the ''"provision has effect for economic, public health, public safety or administrative purposes"''. In addition ''"Nothing in these Regulations shall apply in relation to any supplementary indication"'' (of which the gallon is one such). One has only to look at any car manufacturer's advertising in the UK to see that "miles per gallon" is still in widespread usage. Large containers are still sometimes advertised by gallon size, though the metric equivalent must now be stated. The article simply states a fact known to be true here, but I can provide a link to some advertising if that would help you to believe it. (<small>I see that you expect me to believe that inches are still used in Canada, and I've no problem with that. </small>) ] 08:13, 3 February 2012 (UTC)

:Although the gallon is no longer allowed as a primary unit for trading (specifically selling by volume), it ''can'' still be used as a secondary unit, and there is no regulation preventing the display of prices by the gallon. Also there is no regulation at all prevending the asking for a volume in gallons or preventing the use gallons in descriptions in the media or in literature. The regulation has a very narrow scope and the "official" position has had little impact on the day-to-day everyday use of the gallon in the UK. The UK still uses gallons. -- ] (]). 09:04, 3 February 2012 (UTC)

::DeFacto is only giving half the story - gallons may be used whern pricing liquids ''as a supplementary measure'' (ie alongside the price per litre '''and''' in a format that is not more prominent that the litre price). Even though DeFacto is a frequent contributor to motoring articles in Misplaced Pages, I have my doubts as to whether or not he actually drives. If he did, he would have noticed that petrol pumps are in litres and prices are advertised in litres (and have been since about 1984) and would have not made ridiculous statements like the one above. I have not seen anything priced by the gallon, even as a supplementary unit for many years. The only place where gallons are used in everyday life in the UK is in fuel consumption which is expressed in mpg alongside "L/100 km". ] (]) 10:01, 3 February 2012 (UTC)

:::Martinvl, I'm flattered that you have researched my editing history. It's a pity you don't read my contributions more carefully before commenting on them in such disparaging terms though. Where did you think that I suggested that petrol prices ''were'' displayed in gallons?
:::I pointed out that it is ''not'' illegal to use gallons in the UK, that's all - for the sake of accuracy and neutrality. Are you familiar with those latter two concepts? -- ] (]). 10:21, 3 February 2012 (UTC)

::::DeFacto - please tell me exactly where gallons are used in the UK today (I know about the use of mpg) - when I buy petrol, it is priced by the litre, when I buy metered water (for household use), it is prioced by the cubic metre, when I buy "large" containers of oil, they are 5 litre containers, so where are gallons actually used? May I also draw your attention to ]. ] (]) 11:12, 3 February 2012 (UTC)

:::::Martinvl, where? All over and by many, and probably most people when they are in need of a unit to measure or describe volumes or capacities of more than a few pints (a few 0.568261485 litres). It is the UK's traditional and cumstomary unit in such cases. I've never seen any evidence to suggest anything different, even since officialdom has relegated the gallon into second place behind the litre for the purposes of selling by volume or capacity. Even motorists, who don't get a choice in how fuel is dispensed. have a spare "gallon can" (even if it's actually a 5-litre plastic "can") and talk about how efficient their cars are in terms of mpg. Have you ever found any evidence, reliably sourced I mean, not from your personal experiences, that the majority of UK people have, at long last, discarded the gallon in favour of the litre? -- ] (]). 13:55, 3 February 2012 (UTC)


== Gallon in Canada ==
Funny you mention pints of 0.568261485 mL. I wonder how many people who go to the pub and get a pint glass realise that those "pint" glasses are really 570 ml? http://www.ledcups.com/penthouse-570ml-pint-glass-only-6-78-each/ This is another example (as in the case of your 5 L can being referred to as a gallon) where the real world uses metric in design and manufacturing and will ignore all of those digits and make it simple. So wouldn't it be best to just refer to a pint as 570 mL and not waste your effort typing all those extra digits that are not real? ] (]) 14:38, 11 March 2012 (UTC)


So we all know that "Gallon" in Canada can mean Imperial or US gallons. But in commercial cooking in Canada "gallon" also means 4 liters in at least some parts of the country. The place where most non-cooks would run into this is a phrase like "can you put a gallon of milk (4L) in the cart?" I do not have a source for this, but I've personally experienced it in 3 different provinces, so I know it happens. I've really grown to loath the fuzziness of the word "gallon". &mdash; ]<sub><small>]</small></sub> 23:22, 25 September 2015 (UTC)
::::::Canada officially allows both the imperial and metric systems to be used. Here's the law mandating usage in Canada ( http://laws-lois.justice.gc.ca/eng/acts/W-6/page-14.html#h-17 ... note: gallon ). The law that forbade the use of gallons in the United Kingdom is a BRITISH law (and not a European directive). To the best of my knowledge, there is no gas station in the United Kingdom that sells fuel by the gallon (whereas there are in Canada -- in the prairie provinces and some Ontario towns). Many products in Canada still come by the gallon (paint for example: http://www.lowes.ca/HowTo/calculator_paint.aspx ... there is a metric option to comply with Canadian law, but I assure you that 99% of Canadians use what's familiar to them -- imperial). I'm not trying to say the gallon has lost currency among the British public as I know it is still used (albeit, INFORMALLY). To the best of my knowledge, there is no statute or officially sanctioned regulation in the United Kingdom that permits the gallon's continued use, whereas in Canada THERE IS (and therein lies the difference). Regarding my "expecting" you to believe inches are still used in Canada, all I can say is you've obviously never been to Canada. Home construction, engineering, cooking, etc, are dominated by inches (and other imperial units for that matter; the foot, the pound, even Fahrenheit--almost NEVER seen, except INFORMALLY, in the United Kingdom--etc). Believe what you want, but here's proof:


:Canada stopped using Gallons in 1979... we buy milk, gas etc... in litres since metrification.
Showcasing "official" use of the inch (section 1.7 "Particulars of the Track" ... also make note of the "official" use of Fahrenheit -- completely nonexistent in British "officialdom"): http://www.tsb.gc.ca/eng/rapports-reports/rail/1996/r96c0135/r96c0135.asp
http://www.weatheroffice.gc.ca/forecast/city_e.html?bc-74&unit=i (the Met Office doesn't offer an imperial option) <span style="font-size: smaller;" class="autosigned">— Preceding ] comment added by ] (]) 07:38, 11 February 2012 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot--> :source: https://www.thecanadianencyclopedia.ca/en/article/metric-conversion <!-- Template:Unsigned --><small class="autosigned">—&nbsp;Preceding ] comment added by ] (] • ]) 00:04, 22 January 2020 (UTC)</small> <!--Autosigned by SineBot-->
::Yes the country metrified, but that's not he same as saying that Canada simply stopped using all imperial units at that time. Many of the imperial units are '''still''' in use. Produce and meat are priced in both metric and imperial units, and the price per pound is the first and largest, and sometimes the only price for example. Some items that are labelled in metric units are still actually in imperial-sized quantities. Butter is sold in 454 gram sticks, exactly one pound, and no-one I know ever says "get 454 g of butter". You might want to actually read the source you are listing... "Despite the shift, many Canadians still express certain measurements in imperial units, such as height (feet and inches)." Transport Canada was still listing miles per gallon for vehicle efficiency as recently as 2010. ] (]) 07:39, 22 January 2020 (UTC)
http://www.foodnetwork.ca/ontv/hosts/anna-olson/recipe.html?dishID=2666&hostid=35047
http://www.foodnetwork.ca/recipes/Eggs/Dairy/recipe.html?dishid=2633
http://www.canadiantire.ca/AST/browse/6/Tools/HandTools/SpecialtyHammers/PRD~0574186P/Estwing+2.5+lb+Mallet.jsp?locale=en
http://www.canadiantire.ca/AST/browse/8/KitchenBath/Bakeware/PizzaPans/PRD~0422635P/Lagostina+Pizza+Pan%2C+14-In.jsp?locale=en
http://www.canadiantire.ca/AST/browse/3/HouseHome/BathroomDecor/ShowerCurtains/PRD~0631311P/Polyester+Shower+Curtain%2C+72+x+72-in.jsp?locale=en


== El Salvador ==
Again, the usage of imperial units in Canada FULLY complies with Canadian law. Apart from road usage and pints, the United Kingdom mandates metric usage only (though I could be mistaken, and am therefore hoping someone can clear up the confusion). In Canada regulations for how food products are to be labeled (using the imperial and metric unit) are also mandated ( http://www.inspection.gc.ca/english/fssa/labeti/guide/ch2e.shtml#a2_6 ). When I was in the UK, my British relatives used metric measurements more than I did. ] (]) 23:56, 10 February 2012 (UTC)


I edited the list of countries section to include the following comment:
:173.180.210.51, in the UK something is allowed unless it is banned by some regulation - so as there is no regulation banning the use of the gallon (or any other imperial unit) then it is allowed, and certainly remains in widespread common use. However, for specific trading purposes and some of the activities of officialdom (law writing, etc.) there are regulations stipulating that a metric unit should be used as the primary unit. What that means in practical terms for those specified regulated activities is that the metric measure ''must'' be given and the imperial measure ''may'' also be given, but no no greater prominence than the metric measure. All of this is described in this article, with references, in the second paragraph of the "Worldwide usage of gallons" section. -- ] (]). 09:56, 11 February 2012 (UTC)


El Salvador announced in December 2020 that it will switch all units not presently metric to metric to be completed by June 2021. https://www.elsalvador.com/noticias/negocios/gasolina-se-vendera-en-litros-2021/786601/2020/
:Yes, the article accurately describes current usage. Fish tanks, hot and cold water tanks, fuel tanks (especially for motor bikes) are still sold primarily by gallon measurements, though most will have the metric equivalent also. I agree that Canada does not have EU directives to annoy it, but the UK does not "mandate metric usage only". ] 12:52, 11 February 2012 (UTC)


User DeFacto reverted the edit claiming; not relevant here yet - wait until we having RSes saying it has happened
::A European Union "directive" wouldn't fly in Canada. The EU would be swiftly told to stuff it. Lol. <span style="font-size: smaller;" class="autosigned">— Preceding ] comment added by ] (]) 20:53, 11 February 2012 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->


Actually it is relevant seeing that the change is not an overnight change but is being done over a period of time to be completed by June 2021. The article states that workshops have been in place since October to educate the companies that are effected about the change.
:::Good for Canada! The EU tends to get a bit annoyed when the UK tells them that! ] 12:45, 12 February 2012 (UTC)


Because the change has been announced, the article on gallons needs to be amended to show the change is presently in progress. I understand that those who are opposed to metrication may be upset that this is happening. The remnant uses of pre-metric or American units in many metric countries are continuing to be removed whether these opposers like it or not. Is hiding the fact and hoping countries like El Salvador change their mind is their goal?
Well, Duh! That is because Canada is not part of the EU. I'm sure though that the UK Luddites are more annoyed by the EU then the reverse. The EU has more power than the UK and has the ability to punish the UK when it becomes too much of a whining annoyance. ] (]) 01:22, 6 April 2012 (UTC)


I think it is the right time to add some form of statement that El Salvador is in the process of completing the change that has been done started over a century ago.
:Oh yes! We enjoy whining at the EU, and I'm not sure which side annoys the other more. As one of the "UK Luddites", I can assure you that we get very annoyed by the EU, but, fortunately, they have no real power. They issue directives, but these are only documents, not laws. Only the British Parliament can make British laws. The EU's power to "punish" is ultimately just expulsion from the "club", and, since it is almost at the point of tearing itself apart over Greece, perhaps that would not be such a disaster! If ever the EU gained real power, I think I would emigrate to Canada! <small>Please don't take my rant too seriously! </small> ] 06:40, 6 April 2012 (UTC)


] (]) 11:40, 18 December 2020 (UTC)
::This discussion is going off-topic. Please read ] and also ignore the trash that is dished up by the editor of the ]. ] (]) 08:27, 6 April 2012 (UTC)


== UK gallon: 62F or 72F? ==
:::Yes, you're right. Sorry for sounding like the Daily Mail (I don't read it often!) I'd forgotten about the ], though Britain is not the only country that thinks it sometimes exceeds its intended powers. Ultimately, it has authority only be the agreement of the British parliament. ] 18:01, 6 April 2012 (UTC)


The article states the pre-1976 British gallon was 10 pounds of water at 62F. However, I can only make the numbers fit at 72F -which is also a more reasonable working temperature.
== someone knows ==
The unit was exported from France to the U.K. so it is not British at all!


So I suspect there is an error but don't know if we can easily access the standard to check for sure. ] (]) 19:48, 23 July 2024 (UTC)
Where does the word gallon come from?according to come from français but I'm not sure because of is a Roman measure or not. measure imperial (Roman empire) --] (]) 06:01, 4 February 2012 (UTC)
:Section expanded a bit, but the "Roman measure" needs further research from somebody. --] (]) 08:19, 4 February 2012 (UTC)


== Mistake in the conversion from roman congius to dm³ ==
== Spam Alert ==


I just reverted linkspam by user Oleh Svintsitskyy who appears to be a professional spammer. All of his edits are linkspam linking to the same site. In just the few minutes that it has taken to write this warning, he has posted more spam. ] (]) 17:34, 11 March 2012 (UTC) Although it is true that the roman congius has 216 cubic in, those are roman in, which are smaller, about 2.47 cm. So it is about 3.24 dm³. This is consistent with accounts that it was equivalent to the volume of 10 roman libras of water, which were about 324g ] (]) 06:00, 15 October 2024 (UTC)
That's ] ] (]) 13:39, 12 March 2012 (UTC)

Latest revision as of 13:52, 24 December 2024

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Ambiguous gallons in 'mpg'.

Many articles mention 'mpg'. This is ambiguous. What do people think is the best way to disambiguate this? For example we could say:

  • 15 US mpg
    I think this is the 'least bad' solution.
  • 15 mpg (US)
    I would prefer this solution because the 'US' is put near the gallon. Unfortunately, the context often requires more parentheses. For example 15 mpg (US) (16 L/100 km)
  • 15 mi/USgal
    Hmm

Thoughts welcome. Please look at article examples to see how this would work in practice. Bobblewik  (talk) 12:55, 20 Jun 2005 (UTC)

  • 15 mi/U.S. gal
  • 15 mi/gal (imp)
If in running text, not just in tables, "miles per imperial gallon" or "miles per U.S. gallon" in first instance, and one of the abbreviated versions thereafter.
If any of them should happen to be used with boats or aircraft, ambiguous miles maybe should be disambiguated as well. I don't see that as much of a problem and can't think of any place where that happens now in Misplaced Pages, just throwing it in for completeness.
Symbols for units of measure should never be italicized, and your use of italics is unclosed. Gene Nygaard 13:34, 20 Jun 2005 (UTC)
I think we can assume US gallons for any contemporary context and only disambiguate the other cases. Actually it is just yet another reason not to use English measures at all. Christoph Päper 14:24, 20 Jun 2005 (UTC)
I've heard that many of the British still use miles per imperial gallon, though they buy their petrol by the litre. Their odometers are still in miles, anyway, so litres per hundred kilometres isn't any easier to calculate. It's even weirder in Canada, where I know many people who buy their gasoline by the litre and whose odometers are in kilometres still figure miles per imperial gallon. Gene Nygaard 05:16, 21 Jun 2005 (UTC)

How do they compute mpg when the purchase is in litres and the odometer is in kilometres? Do they really bother to do a complex computation or just guess? BTW, which mpg is used in Canada? — Preceding unsigned comment added by 68.109.207.69 (talk) 12:50, 18 December 2011 (UTC)

The imperial gallon is still used when 'mpg' is quoted in Britain. As far as I know it is the dominant unit that British people use when discussing fuel efficiency even though fuel is sold in litres, not gallons. Manufacturers still quote it, for example Ford UK says the Focus does 8.7 L/100 km (32.5 mpg). Furthermore, in-car fuel efficiency displays quote 'mpg' and mean the imperial gallon. Many British readers assume that 'mpg' refers to the imperial gallon because they are not aware of any other gallon. I suspect that the same would apply in other countries. Bobblewik  (talk) 10:40, 21 Jun 2005 (UTC)
Are there any actual article examples where mpg is used and there is an ambiguity over which mpg is being referenced? I think it's safe to assume that if the article is about a Cadillac then it's US mpg, and if it's about an Aston Martin, then imperial mpg. But a Volkswagen or a Honda would be less obvious. Still, this entire discussion seems hypothetical. Firejuggler86 (talk) 00:33, 5 April 2021 (UTC)
If mpg is used, ever, then it is ambiguous and should be converted to (eg) L/(100 km). Dondervogel 2 (talk) 08:55, 5 April 2021 (UTC)
Firejuggler86, the {{convert}} template disambiguates them by rendering them as either mpg‑imp or mpg‑US. -- DeFacto (talk). 09:45, 5 April 2021 (UTC)

Gallon in Canada

So we all know that "Gallon" in Canada can mean Imperial or US gallons. But in commercial cooking in Canada "gallon" also means 4 liters in at least some parts of the country. The place where most non-cooks would run into this is a phrase like "can you put a gallon of milk (4L) in the cart?" I do not have a source for this, but I've personally experienced it in 3 different provinces, so I know it happens. I've really grown to loath the fuzziness of the word "gallon". — Gopher65talk 23:22, 25 September 2015 (UTC)

Canada stopped using Gallons in 1979... we buy milk, gas etc... in litres since metrification.
source: https://www.thecanadianencyclopedia.ca/en/article/metric-conversion — Preceding unsigned comment added by Bitgrazer (talk • contribs) 00:04, 22 January 2020 (UTC)
Yes the country metrified, but that's not he same as saying that Canada simply stopped using all imperial units at that time. Many of the imperial units are still in use. Produce and meat are priced in both metric and imperial units, and the price per pound is the first and largest, and sometimes the only price for example. Some items that are labelled in metric units are still actually in imperial-sized quantities. Butter is sold in 454 gram sticks, exactly one pound, and no-one I know ever says "get 454 g of butter". You might want to actually read the source you are listing... "Despite the shift, many Canadians still express certain measurements in imperial units, such as height (feet and inches)." Transport Canada was still listing miles per gallon for vehicle efficiency as recently as 2010. Meters (talk) 07:39, 22 January 2020 (UTC)

El Salvador

I edited the list of countries section to include the following comment:

El Salvador announced in December 2020 that it will switch all units not presently metric to metric to be completed by June 2021. https://www.elsalvador.com/noticias/negocios/gasolina-se-vendera-en-litros-2021/786601/2020/

User DeFacto reverted the edit claiming; not relevant here yet - wait until we having RSes saying it has happened

Actually it is relevant seeing that the change is not an overnight change but is being done over a period of time to be completed by June 2021. The article states that workshops have been in place since October to educate the companies that are effected about the change.

Because the change has been announced, the article on gallons needs to be amended to show the change is presently in progress. I understand that those who are opposed to metrication may be upset that this is happening. The remnant uses of pre-metric or American units in many metric countries are continuing to be removed whether these opposers like it or not. Is hiding the fact and hoping countries like El Salvador change their mind is their goal?

I think it is the right time to add some form of statement that El Salvador is in the process of completing the change that has been done started over a century ago.

Ametrica (talk) 11:40, 18 December 2020 (UTC)

UK gallon: 62F or 72F?

The article states the pre-1976 British gallon was 10 pounds of water at 62F. However, I can only make the numbers fit at 72F -which is also a more reasonable working temperature.

So I suspect there is an error but don't know if we can easily access the standard to check for sure. Man with two legs (talk) 19:48, 23 July 2024 (UTC)

Mistake in the conversion from roman congius to dm³

Although it is true that the roman congius has 216 cubic in, those are roman in, which are smaller, about 2.47 cm. So it is about 3.24 dm³. This is consistent with accounts that it was equivalent to the volume of 10 roman libras of water, which were about 324g 200.173.209.114 (talk) 06:00, 15 October 2024 (UTC)

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