# The United States and the metric system. **URL:** \ **Category:** Factual Questions\ **Created:** [October 17, 2009, 6:01am UTC](https://boards.straightdope.com/t/the-united-states-and-the-metric-system/514126 "2009-10-17T06:01:02Z")\ **Posts on this page:** 8\ **Page:** 7
**Author:** ![Flymaster](https://avatars.discourse-cdn.com/v4/letter/f/c4cdca/32.png) [@Flymaster](https://boards.straightdope.com/u/Flymaster)\ **Post date:** [October 22, 2009, 3:51am UTC](https://boards.straightdope.com/t/the-united-states-and-the-metric-system/514126/121 "2009-10-22T03:51:55Z")
> [@bengangmo](#): > > unless you actually need 35mm or 60mm… > > Let me ask you this then.. > > which would you rather work out (using mental arithmetic, and which is less likely to be wrong? > > 1. 13 metres by 22 metres by 3 cm, > > or > > 1. (43’ 4" x 73’ 4" x 1.4" )\* / 3 (for this amount you need to buy in cubic yards right, and 3 cubic feet is 1 cubic yard?) > > the first one I can do in my head, the second I can’t > > I can’t be bothered going to online calculator so I just converted at 25mm = 1 inch Obviously I’d rather do the first. And no, 9 cubic feet is 1 cubic yard. But I wouldn’t have built a 20m x 20m x 25cm hole in my back yard. I’d have built a 60ft x 60ft x 1 inch hole. And then I’d rather do that in feet than do it in exact metric conversions. I can do the 60x60xinch in my head, but can’t do the metric version of that. It’s exactly as easy to do round-ish metric numbers in your head as it is to do round-ish imperial numbers in your head, when it comes to volume defined as “cubic units” when the dimensions of the volume are “units”. Neither side has an argument for superiority here, and to claim that it’s somehow easier to do it in meters just because the hole happens to be conveniently metric is just ridiculous. ---
**Author:** ![Flymaster](https://avatars.discourse-cdn.com/v4/letter/f/c4cdca/32.png) [@Flymaster](https://boards.straightdope.com/u/Flymaster)\ **Post date:** [October 22, 2009, 3:52am UTC](https://boards.straightdope.com/t/the-united-states-and-the-metric-system/514126/122 "2009-10-22T03:52:59Z")
> [@bengangmo](#): > > So your tape measure doesn’t show 6 feet 5 inches then? It shows 6.4167 feet? > > Why didn’t I convert for metres - because there is no need to… 0.4 metres is the same as 40 cm is the same as 400 mm…for feet it’s not as intuitive - unless of course you wanna tell me that 6’7" is the same as 6.7 feet. It’s not. It’s the same as 7 feet, when I’m trying to paint a wall. ---
**Author:** ![Flymaster](https://avatars.discourse-cdn.com/v4/letter/f/c4cdca/32.png) [@Flymaster](https://boards.straightdope.com/u/Flymaster)\ **Post date:** [October 22, 2009, 4:01am UTC](https://boards.straightdope.com/t/the-united-states-and-the-metric-system/514126/123 "2009-10-22T04:01:38Z")
And I’m being serious when I say that it’s 7 feet. Nobody builds a wall that is 6’7.322" tall. Because that would be insane. In imperial-unit places, walls are sensible imperial units. Just like we use letter sized paper and Europe uses A4. This is important to realize when arguing either side of the issue. ---
**Author:** ![bengangmo](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@bengangmo](https://boards.straightdope.com/u/bengangmo)\ **Post date:** [October 22, 2009, 4:05am UTC](https://boards.straightdope.com/t/the-united-states-and-the-metric-system/514126/124 "2009-10-22T04:05:11Z")
> [@Flymaster](#): > > Obviously I’d rather do the first. And no, 9 cubic feet is 1 cubic yard. > > But I wouldn’t have built a 20m x 20m x 25cm hole in my back yard. I’d have built a 60ft x 60ft x 1 inch hole. And then I’d rather do that in feet than do it in exact metric conversions. I can do the 60x60xinch in my head, but can’t do the metric version of that. > > It’s exactly as easy to do round-ish metric numbers in your head as it is to do round-ish imperial numbers in your head, when it comes to volume defined as “cubic units” when the dimensions of the volume are “units”. Neither side has an argument for superiority here, and to claim that it’s somehow easier to do it in meters just because the hole happens to be conveniently metric is just ridiculous. That works fine if you happen to have a perfectly round number to work with - I can also work out something like 21.4m x 27.8m x 46mm with mental arithmetic if I happen to have an odd shaped area. Its not a matter of superior its a matter of easier - its not hard to do 214 x 278 x 46 mentally, then put in the decimal point as you see fit. I do find it hard though to do something like 79’5" x 123’ 7" x 1.5" unless I first convert the inches in decimal feet - which if you’re going to do that, why not just use metric in the first place? ---
**Author:** ![Critical\_Mass](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@Critical\_Mass](https://boards.straightdope.com/u/Critical_Mass)\ **Post date:** [October 22, 2009, 4:29am UTC](https://boards.straightdope.com/t/the-united-states-and-the-metric-system/514126/125 "2009-10-22T04:29:26Z")
> [@Flymaster](#): > > And no, 9 cubic feet is 1 cubic yard. Want to try 27 cubic feet to a cubic yard? ---
**Author:** ![Saltire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saltire/32/553_2.png) [@Saltire](https://boards.straightdope.com/u/Saltire)\ **Post date:** [October 22, 2009, 4:30am UTC](https://boards.straightdope.com/t/the-united-states-and-the-metric-system/514126/126 "2009-10-22T04:30:18Z")
> [@Flymaster](#): > > And no, 9 cubic feet is 1 cubic yard. Nitpick: 27 cubic feet (3[sup]3[/sup]) is 1 cubic yard. ---
**Author:** ![Flymaster](https://avatars.discourse-cdn.com/v4/letter/f/c4cdca/32.png) [@Flymaster](https://boards.straightdope.com/u/Flymaster)\ **Post date:** [October 22, 2009, 10:41am UTC](https://boards.straightdope.com/t/the-united-states-and-the-metric-system/514126/127 "2009-10-22T10:41:28Z")
> [@Critical\_Mass](#): > > Want to try 27 cubic feet to a cubic yard? I’d love to, because I’m an idiot. Of course, that doesn’t mean the average person knows how many cc are in a liter, either, but yeah. That hurts my argument. ---
**Author:** ![bengangmo](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@bengangmo](https://boards.straightdope.com/u/bengangmo)\ **Post date:** [October 22, 2009, 11:25am UTC](https://boards.straightdope.com/t/the-united-states-and-the-metric-system/514126/128 "2009-10-22T11:25:36Z")
> [@Flymaster](#): > > I’d love to, because I’m an idiot. Of course, that doesn’t mean the average person knows how many cc are in a liter, either, but yeah. That hurts my argument. Hmm..depends on you meaning of “average” and “know” - but yeah, if you stopped a European on the street and asked, how many cc in a litre, I don’t doubt that the majority would give a blank look. I would bet though that if people were told to guess at what might be the right answer, a lot would get it right. I would further bet that a whole hell of a lot more people know how many cc in a litre than could tell you the number of cubic inches in a gallon. [Previous page](https://boards.straightdope.com/t/the-united-states-and-the-metric-system/514126.md?page=6)