Talk:United States customary units

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US is the only industrialized nation...[edit]

"The US is the only industrialized nation that does not mainly use the metric system in its commercial and standards activities"

  • Well, on a de facto level, Canada also doesn't mainly use the metric system in its commercial and standards activities, its about 50/50. (talk) 21:27, 19 May 2009 (UTC)

I disagree with the above, any Cdn under 40 lives predominantly in metric. Gas is sold in litres, speed limits are metric, milk is in litres, we know and report temperature in celsius, it's really only human heights and weight in imperial (informally, not officially) and fruits and veg in supermarkets (though the usually get rung up in metric, but advertised in imperial) — Preceding unsigned comment added by (talk) 16:42, 27 August 2015 (UTC)

Actually that's wrong. Officially speaking both the USA and Canada use SI to define everything. Canada has brought the use of SI right to the consumer in almost every case. There are still exceptions such as lumber dimensions-though it's worth pointing out that the official sizes of the lumber and the calibrations of the machines are in SI. Masses of goods are measured in grams and kilograms. Volumes of liquids in litres or millilitres. Distances are metres and kilometres (and speeds in km/hr). Temperatures are in °C. Any official weigh scale or measuring device is properly calibrated in SI units and configured to display those. So Canada does far more than half its commercial activity in SI. — Preceding unsigned comment added by (talk) 16:05, 23 August 2013 (UTC)
It would be a really hard issue to put a number on. For example, would you go by number of units sold or by cost? If shoppers seem to pay attention to the customary number on the label, but it would be illegal to market the item without an SI quantity on the label, does that count as customary or SI? Lots of tricky questions. --Jc3s5h (talk) 22:06, 19 May 2009 (UTC)
Well, when you say "3 inches" you are actually saying "3 x 25.4 mm" since "inch" is defined in terms of mm. The "inch" does not exist as an independent/organic unit of measurement, but merely as a multiple of the metre. I guess you could label products with a little bit of mathematics: what's to stop a label saying "LENGTH: 101.6 mm = 4 x 25.4 mm"? That is totally SI compliant, and the fact that 1 inch = 25.4 mm is something everyone using inches should know anyway (education system notwithstanding). (talk) 10:58, 21 February 2010 (UTC)
I could think of something to stop a label saying "LENGTH: 101.6 mm = 4 x 25.4 mm". JIMp talk·cont 01:21, 17 February 2011 (UTC)
Why is the US the only developed country to stand out against the international metric system? It always seemed odd to me that American's should hold so steadfastly to a pre-1824 British system of weights and measures. Talk about being backward... — Preceding unsigned comment added by (talk) 20:14, 27 August 2011 (UTC)
Maybe for the same reason that some people still grow their own vegetables, shop organic, and prefer heirloom varieties to the corporate agribusiness foods that the big supermarket chains sell. Or for the same reason that the Chinese, Japanese, Koreans, Russians, Arabs, Hindus, and Israelis still aren't using the "modern" alphabet. Zyxwv99 (talk) 18:32, 26 November 2011 (UTC)
You're an ass.Jersey John (talk) 09:06, 29 November 2011 (UTC)

Hmm... I think this sentence is somewhat misleading. According to the source:

"At this time, only three countries - Burma, Liberia, and the US - have not adopted the International System of Units (SI, or metric system) as their official system of weights and measures. Although use of the metric system has been sanctioned by law in the US since 1866, it has been slow in displacing the American adaptation of the British Imperial System known as the US Customary System. The US is the only industrialized nation that does not mainly use the metric system in its commercial and standards activities, but there is increasing acceptance in science, medicine, government, and many sectors of industry."

Even in this discussion, at least one person has made the mistake of thinking the US is the only country not to adopt SI units. I think the first fact is more solid; "mainly" as a description is both ambiguous and subject to change. --Carbon Rodney 06:57, 28 August 2012 (UTC)

There's been some discussion of Burma and Liberia on other weights-and-measures related articles. Apparently Liberia has already gone metric, while Burma's target date is some time in 2012. I think Burma has met it's goal already, except for land measurement, which is still in imperial units. The most commonly cited source for this kind of information is the Weights and Measures appendix to the CIA World Factbook. However, the print edition is one year behind the online edition, which is one year behind the classified edition. Also, no guarantee that Appendix G is up-to-date in any edition. Zyxwv99 (talk) 13:04, 28 August 2012 (UTC)
Thanks for the info. The edition info on the web page is not clear; it states the Factbook is updated every week. That's more like editorial changes though. -Fnlayson (talk) 17:26, 28 August 2012 (UTC)


"... and U.S. medical practitioners often use degrees Fahrenheit for body temperature."

I think you'd be hard pressed to find a hospital, clinic, or doctors office in the US that doesn't use F. Saying often seems to underplay the near ubiquity of F in medical use. Maybe change often to generally or usually or almost always? (talk) —Preceding undated comment added 06:38, 11 February 2010 (UTC).

My recollection in the last few years is some US medical treatment locations use Celsius, some use Fahrenheit. I think a source is needed that conducted some kind of survey in order to know the best word to use. Jc3s5h (talk) 16:00, 11 February 2010 (UTC)
As of late, the more elite hospitals are switching to full metric usage. Something to do with minimizing conversion errors, misdosing of drugs, especially for children. Medical institutions that tend to cater to the lower classes will continue to dumb down units. (talk) 16:50, 13 October 2012 (UTC)


Is the pound considered to be a unit of force or mass in the U.S. ? Here in the UK the lb is obsolete, but it was legally defined as a unit of mass, equivalent to a stated fraction of a kg in the Weights & Measures Act (1963), and there is never any ambiguity about it. But judging from what I have seen on the internet this is a matter of controversy and confusion in the USA. Do you have anything equivalent to an Act of Parliament over there which gives an authoritative answer to this question ? A related point is that historically in England, up until 1963, the pound Avoirdupois was considered to be a force or weight. So the historical aspects of the main article are incorrect in discussing the historic English unit under the heading of mass. Anyone who is interested in the history of this unit would be sensitive to this matter, so I think it should be corrected. In anticipation of any dispute over this, I will refer to the Weights and Measures Acts of 1878 and 1958 and 1963, and also, as a matter of technical interest, to 'Useful Rules and Tables' by W J M Rankine, (Professor of Engineering at Glasgow University, and originator of the Rankine Cycle) London, 1889. Rankine defines weight as a gravitational force (p 305), and the lb as the weight of a certain piece of platinum under stated conditions of temperature, atmospheric pressure, and location (all pertinent to the weight of a certain mass) on p 97. On p 245, Rankine defines absolute units of force (as distinct from units of weight) thus - ‘Absolute units of force in the weight of an unit of mass: in British units 32.2 nearly…’ (p 245). This can be interpreted as meaning that the absolute unit of force in the British system is 1/32 lb-wt. Furthermore, in giving a rule for calculating centrifugal force (p 246), Rankine states - 'Multiply the weight of the mass by the square of its linear velocity and divide by the radius. The result will be in absolute units which may be converted into units of weight by dividing by g'. This rule only makes sense if 'the weight of the mass' is measured in pounds. Thus if we take a certain mass having a weight (gravitational force) of 1 lb-wt, rotating with a speed of 1ft/sec at one foot radius, the centrifugal force will be 1 absolute unit or 1/32 lb-wt, which is correct. The 'absolute force unit' of ~1/32 lb-wt was called the poundal in the foot-pound-second system, and was defined as the force required to accelerate a mass of 1lb at 1ft/sec^2. In the UK the pound changed from being a force unit to being one of mass in 1963; compare the Weights and Measures Acts of 1958 and 1963; the former defines the pound by reference to the W & M Act of 1878 in which the pound is a weight, while the latter explicitly states that the pound is a mass. Dr A. J. Smith CEng Sept 2010 —Preceding unsigned comment added by (talk) 13:39, 20 September 2010 (UTC)

For purposes of trade and commerce, the pound is a mass in the US; see Refinement of values for the yard and the pound. However, it is used as a unit of force as well, and which is intended must be determined by context. Jc3s5h (talk) 14:45, 20 September 2010 (UTC)
MONDAY, December 17th, 1792.
Agreeably to the order of the day, the Senate resumed the consideration of the report of the committee made April the 5th, 1792, on the subject of weights and measures, together with the motion made thereon the 6th instant—Whereupon,
A motion was made to postpone the consideration thereof, and to
Resolve, That the present measures of length be retained and fixed by an invariable standard; that the measures of surface remain as they are, and be invariable also as the measures of length to which they are to refer; that the unit of capacity now so equivocal, be settled at a medium and convenient term, and defined by the same invariable measures of length, that the more known terms in the two kinds of weights be retained, and reduced to one series, and that they be referred to a definite mass of some substance, the specific gravity of which never changes; and that a committee be appointed to bring in a bill accordingly—and after debate,
Ordered, That the consideration of this motion be deferred until tomorrow.
6th. That the unit of weights shall be a pound, which shall be equal to the pound Avoirdupois, now in use, and shall be equal in weight to a quantity of rain water, twenty cents of a foot square, and forty cents deep, or sixteen thousand cubic cents of a foot, measured and weighed in a cellar of uniform natural temperature.
-- Journal of the Senate of the United States of America: being the second session of the Second Congress, begun and held at the city of Philadelphia, November 5th, 1792, and in the seventeenth year of the sovereignty of the said United States.
Printed by John Fenno, 1792 - 100 pages

Zyxwv99 (talk) 02:30, 18 November 2011 (UTC)

Troy weights[edit]

This is not correct:

"To alleviate confusion, it is typical when publishing non-avoirdupois weights to mention the name of the system along with the unit. Precious metals, for example, are often weighed in "troy ounces", because just "ounce" would be more likely to be assumed to mean an ounce avoirdupois."

Look at the troy ounce article. There's a picture of a gold bar that has the word "ONE OUNCE FINE GOLD" stamped on it. Go to Google Images and try finding a picture of a bar of gold that has the word "troy" on it. Lots of bars denominated in ounces, but they don't say troy. In the precious metals trade, when you say "ounce" people just assume you mean troy. In academic, encyclopedic writing, you would of course be more specific, but I mean "in the trade" which is essentially common usage.Zyxwv99 (talk) 01:57, 18 November 2011 (UTC)

The case of ounce being stamped into gold bullion (or any other precious metal) is an excellent example of the context clearly meaning the weight is not avoirdupois. But having "ounce" written generally, or associated with most household or industrial goods would almost certainly imply avoirdupois. —EncMstr (talk) 03:59, 18 November 2011 (UTC)

History section NOT about the history of the USCU?[edit]

so the history part of the article is about the metric system and not about the USCU at all! what's up with this? Robow87 (talk) 13:46, 4 February 2013 (UTC) — Preceding unsigned comment added by Robow87 (talkcontribs) 13:43, 4 February 2013 (UTC)

The History section is merely misnamed. It explains the anomaly that the US is still not properly metricated, and in fact is the most backwards country in the world in that respect.
There isn't much obvious information (of the kind that always gets added to Wikipedia articles) about the history of the US customary units in general. There is a lot to say about individual units, and that historical information belongs with the detailed discussion of those units. Hans Adler 14:52, 4 February 2013 (UTC)
No reason for such negative and biased comments about the system and the US. This is not a discussion forum. Maybe you should take that to another site... -Fnlayson (talk) 17:55, 4 February 2013 (UTC)
Sorry if you don't like reality's 'liberal' bias, which may have been a bit too obvious from my summary of the section that is now titled "Background". My post was on what to do with this article. Do you have something to contribute to that topic? Hans Adler 19:55, 4 February 2013 (UTC)
A nice scholarly annotated neutral discussion about how a country with a proprietary and obsolete system of weights and measures was able to take on the metric world in battle and win, would be quite informative. --Wtshymanski (talk) 20:18, 5 February 2013 (UTC)


Should the Jack ( (half a gill) be included in the list of volumes? Also, it may be helpful to include a table that shows the units related by a factor of 2. Jimktrains (talk) 20:39, 1 August 2013 (UTC)

Dispute over "agreed to"[edit]

The article contains the following sentence:

This definition was agreed with the United Kingdom and other Commonwealth countries, and so is often termed international measure.

It should read,

This definition was agreed to with the United Kingdom and other Commonwealth countries, and so is often termed international measure.

I corrected it, and NebY (talk · contribs) reverted my correction. The sentence is incorrect because agree is not a transitive verb. The parties did not "agree the definition": they agreed to it. The sentence would mean the same if it were written without the passive construction:

The United States agreed to this definition with the United Kingdom and other Commonwealth countries, so the definition is often termed international measure.

but the passive construction is appropriate, since the definition, not the United States, is the focus of the sentence. The sentence should stand as I corrected it.

J. D. Crutchfield | Talk 20:22, 25 March 2015 (UTC)

Why not just rewrite the sentence to avoid the disputed usage, if it's possible to do so clearly and succinctly? - BilCat (talk) 20:25, 25 March 2015 (UTC)
That would save me from rehearsing the evidence for the transitive use of "agree", which goes back to the sixteenth century and thrives today. How about
This definition formed part of a treaty with the United Kingdom and other Commonwealth countries, and so is often termed international measure
This definition formed part of a treaty between the United States, the United Kingdom and other Commonwealth countries, and so is often termed international measure? NebY (talk) 20:56, 25 March 2015 (UTC)
Or that will do nicely - thanks Fnlayson! NebY (talk) 21:01, 25 March 2015 (UTC)
  • You're welcome and thanks for the clean-up. -Fnlayson (talk) 21:12, 25 March 2015 (UTC)

Either of NebY's proposed alternatives would suit me, and would be better than what an intervening editor has done. As a matter of personal curiosity, I would be grateful to see some of the evidence NebY mentions, though of course not here. I can be reached via email through Wikipedia, if NebY will be so kind. J. D. Crutchfield | Talk 21:06, 25 March 2015 (UTC)

The issue seems to be a US/British grammar thing. See here for some explanation. After reading that, I still couldn't figure out which was the correct form in American English, as it seemed awkward either way, which is why I suggested rewriting it. :) - BilCat (talk) 21:55, 25 March 2015 (UTC)
Thanks for the link. J. D. Crutchfield | Talk 22:00, 25 March 2015 (UTC)

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