# Whats the deal in USA with 1 litre soda pop, is USA on metric? **URL:** \ **Category:** Factual Questions\ **Created:** [August 21, 2002, 1:23am UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825 "2002-08-21T01:23:23Z")\ **Posts on this page:** 20\ **Page:** 6
**Author:** ![wolfpup](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wolfpup/32/10618_2.png) [@wolfpup](https://boards.straightdope.com/u/wolfpup)\ **Post date:** [July 29, 2017, 7:52pm UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/101 "2017-07-29T19:52:43Z")
> [@kanicbird](#): > > Well that’s the rub, the imperial system is based on human life experiences. Metric is not. Imperial will always be a more natural unit of measurement than metric, though if born under metric rule one can adapt and live a perfectly normal life. Actually, imperial measures are based on medieval concepts like the size of the King’s limbs and appendages. Metric comes from a period of science and enlightenment and an attempt to have measures based on rationalism. Although at least you acknowledge that it might be possible to “live a normal life” despite the misfortune of being born under “metric rule”, which I take it to mean something like “metric dictatorship”. 😃 Personally I don’t see how it’s possible to live a normal life measuring distances in kilometers. I mean, you always have to remember that there are 1000 meters in one (or worse, that there are 500 meters in half a kilometer or 4000 meters in 4 kilometers), instead of the natural order of things based on human experience that a mile contains 5,280 units the length of the King’s feet, or 1,760 units of the distance from King Henry I’s nose to the thumb of his out-stretched arm. Yet somehow virtually the whole world manages to do it. 😉 ---
**Author:** ![rat\_avatar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rat_avatar/32/255_2.png) [@rat\_avatar](https://boards.straightdope.com/u/rat_avatar)\ **Post date:** [July 29, 2017, 11:49pm UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/102 "2017-07-29T23:49:58Z")
> [@wolfpup](#): > > The fact that US traditional units are officially defined in terms of metric units is completely irrelevant to common usage and therefore to this discussion. Argue for metric or against it, but you surely are not trying to argue that this bit of esoterica somehow makes the US a metric country? It has as little relevance in typical usage as the official definitions of the base metric units themselves. When I’m measuring a carpet for the family room I really have zero concern with whether a meter is defined in terms of the earth’s geometry, the distance between scratches on a platinum-iridium bar in Paris, or how far light travels in a vacuum in some tiny fraction of a second. I only care that everyone is using the same units and that my tape measure reasonably conforms to it! > > The meaning of “main standard” is not complicated. Outside of the three named countries – the US, Myanmar, and Liberia – everything is metric with specific enumerated exceptions. Weather reports and forecasts are in Celsius degrees, all or almost all food items and commodities are sold in grams, kilograms, milliliters or litres, etc, and that includes the UK. That there are exceptions doesn’t change the predominant system of measures. Admittedly, the use of miles and MPH and the like for road signage is a rather surprisingly big exception in the UK, but they use metric for just about everything else. > > Anyway, this was all a digression from my comment in #80, where I found it quite humorous that someone had declared that traditional units were superior because humans have an “instinctive” understanding of how far a mile is. Apparently we’re born with it. Whereas one assumes by implication that only French communists have any idea how far a kilometer is, and it’s doubtful that even they know! 😃 First of all, Celsius is not the SI unit of temperature, that is Kelvin, And outside of a metaphysical differentiation, the Fair Packaging and Labeling Act required almost universal dual labeling in 1991. To me the primary issue is that the world use the same basis units, which has been true for the US for over a century. But you may want to google ‘Directive 2007/45/EC’ which recently deregulated packaging in the EU to allow more customary units to be the packaging size. But as legal documents are easier for me to read in English let me stick to the UK: \*the mile, yard, foot and inch for road traffic signs, distance and speed measurement, \*the imperial pint for the dispensing of draught beer and cider, and for the sale of milk in returnable containers, - the acre for land registration,[f] - the troy ounce for transaction in precious metals.[70][99][100] So yes that claim seems to be arbitrary, All US federal agency are compelled to use the Metric system, almost all food stuffs require dual labeling, and all units are just offsets off of the SI units (Like Celsius). So really if we ignore the road signs, and real-estate exceptions that allows the UK to claim, it is only the sale of fuel etc…that really differs. The arbitrary, undefined threshold for the claim above seems clearly to be based on selection bias. As this is General Questions how about a cite or a definition of what that bar is? Because to me it is not so obvious, this is obviously not a binary state and various stages of metrication are in place around the world. Heck even in Canada it is a mix, where wine is sold by the ml, but served in restaurants by the OZ, and beef is advertised and sold by the pound. Canada has metric speed and distance signs, so are they more advanced than the UK? But the primary issue is that the above claim is making a moral judgement, and this site shows that it is fokelore and misinformation. [ > [@](#): > > Folklore suggests that three countries don’t use the metric system — the U.S., Liberia, and Myanmar/Burma — while all others do. In reality, virtually all countries use the metric system, and the question of who is and isn’t metric (see below) is difficult to answer. ]([FAQ: Frequently Asked Questions about the metric system](https://web.archive.org/web/20121004023803/http://lamar.colostate.edu/~hillger/faq.html#how-tell)) So in the spirit of “fighting ignorance” I am asking for cites, and to be clear outside of the special use cases I have explained before I am not anti-SI, but I also don’t think it is a huge priority. Almost all of the big media stories about conversion errors like the Mars Climate Orbiter were due to people not directly calling out the units, and while the metric system solves some very common issues it mandates that you call out units for all critical functions. The addition of µ, c, d, da, h, k, M, etc… prefixes require it (but it is good form anyway) ---
**Author:** ![silenus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/silenus/32/166_2.png) [@silenus](https://boards.straightdope.com/u/silenus)\ **Post date:** [July 30, 2017, 1:05am UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/103 "2017-07-30T01:05:33Z")
Everybody is forgetting the heinous origin of the metric system, and why it is shunned by all right-thinking people of the world: It’s French. ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [July 30, 2017, 1:14am UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/104 "2017-07-30T01:14:26Z")
> [@Reeder](#): > > Coke has come back out with 16.9 oz plastic bottles in twelve packs just recently. Which happen to be 500ml bottles… ---
**Author:** ![septimus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/septimus/32/410_2.png) [@septimus](https://boards.straightdope.com/u/septimus)\ **Post date:** [July 30, 2017, 1:17am UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/105 "2017-07-30T01:17:05Z")
> [@Enola\_Straight](#): > > If suddenly we began selling gasoline at 36 cents a liter and measured the power in Kilowatts, the average American would think somebody had found out a new way to cheat him. True 15 years ago and true today. It’s why clever businesses have been using European for electrical measurements. They sell us an expensive 15-watt new-fangled light bulb and try to tell us it’s the same as a 60-watt real lightbulb. Americans would catch on quicker if they told the truth in _American_ units: 15 watts is only about a fiftieth of a horse-power. (How many dog-power is that?) > [@neutron\_star](#): > > Turning my thermostat from 72 to 73 would produce a more subtle change than turning it from 23 to 24. I like that This is a real problem at my home. A thermostat setting of 28 is too warm and 27 is too cool. I’d like to set it at 27.5 but that is not an option. Instead I alternate between 28 and 27 every 15 minutes or so, based on wife’s prodding! ---
**Author:** ![silenus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/silenus/32/166_2.png) [@silenus](https://boards.straightdope.com/u/silenus)\ **Post date:** [July 30, 2017, 1:28am UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/106 "2017-07-30T01:28:52Z")
> [@bump](#): > > Which happen to be 500ml bottles… Just a heads-up, **bump**. **Reeder** ’s been dead for 5 years. ---
**Author:** ![pulykamell](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pulykamell/32/3166_2.png) [@pulykamell](https://boards.straightdope.com/u/pulykamell)\ **Post date:** [July 30, 2017, 1:29am UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/107 "2017-07-30T01:29:24Z")
> [@Chronos](#): > > Should, maybe, but how many actually do? I’d wager that most don’t, especially among the subset of the population who claim to not understand metric. Good question. I suppose it depends on how you define “experienced cooks.” I was taught from a relatively early age (even before cooking) that the units go: 1 teaspoon, then 3 teaspoons in a tablespoon, then 4 tablespoons in a quarter cup, then obviously 4 of those for a cup, two cups to a pint, two pints to a quart, four quarts to a gallon. Oh, and 8 fluid ounces to a cup. Yeah, that is a whole mess of confusing, isn’t it? What does tick me off is doing recipes by weight in Imperial. Scaling them is a bit of a pain in the ass, especially since my scale doesn’t do ounces past a certain point and goes to pounds and ounces. So if I scale a recipe and end up with 58 ounces, I have to divide by 16 and then take the remainder to find it’s 3 pounds, 10 ounces. For that reason, I do all my by weight recipes (like baked goods and bulk sausage) in metric units. So much easier to deal with. ---
**Author:** ![septimus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/septimus/32/410_2.png) [@septimus](https://boards.straightdope.com/u/septimus)\ **Post date:** [July 30, 2017, 2:02am UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/108 "2017-07-30T02:02:30Z")
> [@DPRK](#): > > Btw [here](https://en.wikipedia.org/wiki/Kahan_summation_algorithm) is one proper algorithm for adding finite-precision decimal numbers. It can be done. Kahan summation isn’t really related to the non-binariness of ten — if that’s your concern, just multiple all your “mils” (or whatever) by 1000 and work with integers. But Kahan summation is a beautiful little method! I am perfectionistic enough that I use Kahan’s method, e.g. when calculating statistical moments. One big caveat for the C programmer: ```auto /* Do NOT compile this with any compiler optimization ! * The optimizer would "figure out" that kp->carry is being set to zero * and eliminate the essence of the method! */ double kahan_add(double addend, struct Floatsum *kp) { double y = addend - kp->carry; double tmp = kp->sum + y; kp->carry = (tmp - kp->sum) - y; kp->sum = tmp; return kp->sum + kp->carry; } ``` ---
**Author:** ![septimus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/septimus/32/410_2.png) [@septimus](https://boards.straightdope.com/u/septimus)\ **Post date:** [July 30, 2017, 2:04am UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/109 "2017-07-30T02:04:03Z")
> [@Flyer](#): > > … the American system [is] FAR, FAR, FAR more intuitive and convenient than the idiotic metric system. > > A foot is very close to the length of the average adult foot. The metric system has no equivalent… > > 25 mph is a good speed for a residential street, which is appropriate, since it’s a fairly small number… Aha! Maybe this explains why America and Europe have diverged: different physical sizes and conditions. Many Americans weigh about 200 pounds — a nice round number. Europeans are more petite and weigh just 65 kilograms. (Who’d ask them to remember they weigh 143.3 pounds?) Similarly, Americans are good enough drivers for 25 mph, while Europeans need the more pusillanimous 30 kph. ---
**Author:** ![Balthisar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/balthisar/32/2825_2.png) [@Balthisar](https://boards.straightdope.com/u/Balthisar)\ **Post date:** [July 30, 2017, 3:32am UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/110 "2017-07-30T03:32:27Z")
> [@Melbourne](#): > > Medicine has been metric since at least the 40’s, when my mother got her training. > > Years after I learned that her idiosyncratic pronunciation of metric terms was a linguistic marker for American medical doctors. Examples? I’m a bit curious. Doctors probably don’t deal in kilometers much, but I’m in the “kill-AH-mudder” camp. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [July 30, 2017, 4:37am UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/111 "2017-07-30T04:37:37Z")
> [@Chronos](#): > > Well of course metric is difficult if you don’t use it. The whole point to going metric is that you’re _not_ converting ml to cups, or kilometers to sections. Right … if we start with metric, then we’re not bothered by conversions … but if grandma’s recipe for dumplings is in cups and pinches, we’d have to convert the metric … and roads are laid out every mile in most of the US, we’re not tearing them all up to put them every kilometer … Townships are typically 6 miles by 6 miles … not sure we’re going to re-survey the whole of the USA … that means conversion factors forevermore … ---
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [July 30, 2017, 9:31am UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/112 "2017-07-30T09:31:56Z")
> [@Balthisar](#): > > Examples? I’m a bit curious. Doctors probably don’t deal in kilometers much, but I’m in the “kill-AH-mudder” camp. The one I found in the linquistics text book was sontometer. The standard pronunciation in Aus is closer to cent-a-meter, and I had no idea where she got that wierd stuff from. ---
**Author:** ![BigT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bigt/32/12044_2.png) [@BigT](https://boards.straightdope.com/u/BigT)\ **Post date:** [July 30, 2017, 9:51am UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/113 "2017-07-30T09:51:29Z")
a^2 + b^2 = c^2 does have rounding when applied to the real world. The second you put measurements on a, b, and c, then you will have to round, as you cannot measure without rounding. Sure, if you are in the hypothetical world of mathematics, you can define something as having a specific exact measurement. But that’s not the real world. As for whether metric is better, I agree the math is easier in your head. But my question is simply “how often do I need to make unit conversions in my head?” It rarely comes up, except in small cases like multiplying a recipe by a fraction, and then I usually do know the answer in my head. I think the best case for switching to metric is simply that everyone else has done it, and we might as well. The best case for not doing so is that there will be a period of confusion as we acclimate to the new system. Neither is particularly compelling to me, but the latter will keep the US away until it actually has to worry about the former being an issue. And computers have basically eliminated that as an issue, even if the U.S. loses its prominence. ---
**Author:** ![BigT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bigt/32/12044_2.png) [@BigT](https://boards.straightdope.com/u/BigT)\ **Post date:** [July 30, 2017, 9:53am UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/114 "2017-07-30T09:53:17Z")
Apparently the answer to the OP’s question is simply that these bottle sizes came about when a lot of people were trying to get the U.S. to convert to metric, and stayed even when that failed because people were used to them. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 30, 2017, 12:45pm UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/115 "2017-07-30T12:45:06Z")
The American system has three main drawbacks, compared to metric, and I deliberately alluded to all three in the sample problems I gave up-thread. The least of the problems is that there are so many conversion factors to learn, like three teaspoons to the tablespoon, two tablespoons to the ounce, and 231 cubic inches to the gallon. Those are annoying to learn, and a lot of people don’t know a lot of them, but you can still work with a unit system that works that way. A bigger problem is that the unit system isn’t what’s called coherent: In a coherent system, the product or quotient of base units will always be another base unit. For instance, power is a mass times a length squared divided by a time cubed, so in a coherent system, the unit of power will be the unit of mass times the square of the unit of length divided by the cube of the unit of time. This happens in metric, where the relevant units are the watt, the kilogram, the meter, and the second, but not in American, where they’re the horsepower, the slug, the foot, and the second. This doesn’t usually affect laymen, but it’s a huge nuisance for scientists and engineers, who deal with such compound quantities all the time. The third and most serious problem with the American system is that it isn’t a standard. People use the same words to mean many different things. “Pound” usually means the weight of 454 grams, unless you’re talking about precious metals, in which case it’s less. Or unless you’re using it to mean the _mass_ of 454 grams, in which case you have a separate unit called the “poundal” for forces. Or maybe you use “pound” to mean both the weight and the force, and have to stick g in all over the place in formulas that have nothing to do with Earth’s gravity. “Ounce” can be a weight or a volume, and even for water (supposedly the basis), the two don’t quite agree. A “ton” can be long or short. A pint’s a pound the world around, as long as by “the world” you mean "only the US, not anywhere in the British Commonwealth, where a pint of water is a pound and a quarter. This one is a problem for everyone, and if a unit doesn’t mean the same thing for everyone, it’s useless. ---
**Author:** ![Acsenray](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/acsenray/32/4519_2.png) [@Acsenray](https://boards.straightdope.com/u/Acsenray)\ **Post date:** [July 30, 2017, 1:11pm UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/116 "2017-07-30T13:11:55Z")
> [@Chronos](#): > > The American system has three main drawbacks, compared to metric, and I deliberately alluded to all three in the sample problems I gave up-thread. The least of the problems is that there are so many conversion factors to learn, like three teaspoons to the tablespoon, two tablespoons to the ounce, and 231 cubic inches to the gallon. Those are annoying to learn, and a lot of people don’t know a lot of them, but you can still work with a unit system that works that way. > > A bigger problem is that the unit system isn’t what’s called coherent: In a coherent system, the product or quotient of base units will always be another base unit. For instance, power is a mass times a length squared divided by a time cubed, so in a coherent system, the unit of power will be the unit of mass times the square of the unit of length divided by the cube of the unit of time. This happens in metric, where the relevant units are the watt, the kilogram, the meter, and the second, but not in American, where they’re the horsepower, the slug, the foot, and the second. This doesn’t usually affect laymen, but it’s a huge nuisance for scientists and engineers, who deal with such compound quantities all the time. > > The third and most serious problem with the American system is that it isn’t a standard. People use the same words to mean many different things. “Pound” usually means the weight of 454 grams, unless you’re talking about precious metals, in which case it’s less. Or unless you’re using it to mean the _mass_ of 454 grams, in which case you have a separate unit called the “poundal” for forces. Or maybe you use “pound” to mean both the weight and the force, and have to stick g in all over the place in formulas that have nothing to do with Earth’s gravity. “Ounce” can be a weight or a volume, and even for water (supposedly the basis), the two don’t quite agree. A “ton” can be long or short. A pint’s a pound the world around, as long as by “the world” you mean "only the US, not anywhere in the British Commonwealth, where a pint of water is a pound and a quarter. This one is a problem for everyone, and if a unit doesn’t mean the same thing for everyone, it’s useless. None of these things are problems for people who are driving to work, checking the weather, buying groceries, etc. Scientists have already switched to metric, decades ago. The only question left is to use government authority to force a change for consumer, retail purposes, and other non-scientific purposes. Industry and commerce will change if and when the benefits outweigh the costs for any particular application. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 30, 2017, 3:16pm UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/117 "2017-07-30T15:16:20Z")
> [@](#): > > None of these things are problems for people who are driving to work, checking the weather, buying groceries, etc. They can be. For instance, a company could switch from measuring their product in fluid ounces to weight ounces, decrease the size by 10%, and leave the labels almost the same so customers can’t tell the difference. ---
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [July 30, 2017, 3:28pm UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/118 "2017-07-30T15:28:50Z")
The gallon = 277 cubic inches, except when it’s 231 or 268 or whatever, has been known to affect “people”. For example when getting ripped off on tax duties, or being served a US pint of beer. Reminds me of the genius attempt to redefine a kilobyte as 1024 bytes (2.4% free!), and traces of that are unfortunately still with us. ETA what **Chronos** said. And there are documented cases of this sort of thing. ---
**Author:** ![Acsenray](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/acsenray/32/4519_2.png) [@Acsenray](https://boards.straightdope.com/u/Acsenray)\ **Post date:** [July 30, 2017, 3:36pm UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/119 "2017-07-30T15:36:27Z")
> [@Chronos](#): > > They can be. For instance, a company could switch from measuring their product in fluid ounces to weight ounces, decrease the size by 10%, and leave the labels almost the same so customers can’t tell the difference. Could they? Would they? Have they? Will they? Is this pure speculation or is it a significant social problem that requires new mandates regarding units of measure that are inadequately addressed by current labeling and fraud laws? ---
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [July 30, 2017, 4:03pm UTC](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825/120 "2017-07-30T16:03:14Z")
From the [Turk Islands](http://www.thebahamasweekly.com/publish/TCI/New_Measures_To_Improve_Tci_Finances_And_Prioritise_Spending_printer.shtml): > [@](#): > > These revenue generating measures, which take effect from 1 December 2011, are: The Customs Processing Fee, which is levied on all imports, will be increased from 4% to 6%. This will generate an additional $2m this financial year and $6m in 2012/13. A switch from the Imperial Gallon to the US Gallon for the purposes of import duty and fuel tax calculations. With one Imperial Gallon equivalent to 1.2 US Gallons, and most beverages and fuel imported from the US, this simplifies how the tariff is calculated. “Simplifies.” Right. The US labelling requirement does require the quantity in metric units, but if it’s in fine print or parenthetical then discrepancies are less obvious. Relevant to the OP’s question, [this](https://www.nist.gov/document-15122) 2009 NIST report found that 17% of products were labelled in metric units only. Progress? [Previous page](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825.md?page=5) [Next page](https://boards.straightdope.com/t/whats-the-deal-in-usa-with-1-litre-soda-pop-is-usa-on-metric/124825.md?page=7)