Talk:Gallon

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 Wikipedia, 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". — Gopher65_talk 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)