# How confusing/unintuitive is the metric system to the average American? **URL:** \ **Category:** Factual Questions\ **Created:** [February 26, 2015, 7:31pm UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698 "2015-02-26T19:31:14Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Cartoonacy](https://avatars.discourse-cdn.com/v4/letter/c/848f3c/32.png) [@Cartoonacy](https://boards.straightdope.com/u/Cartoonacy)\ **Post date:** [February 26, 2015, 10:07pm UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/21 "2015-02-26T22:07:18Z")
> [@aceplace57](#): > > Small changes in F mean nothing. I’m equally comfortable at 61 degrees as I am at 69. Same thing for 41 or 50F. A nine or 10 degree change makes no real difference. It’s basically the same weather. Says you. 😉 My wife puts on two sweaters if the living room thermostat goes below 73. I start perspiring if it hits 75. (That’s 22.8 to 23.9 in C.) We share a very narrow comfort margin. ---
**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:** [February 26, 2015, 10:14pm UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/22 "2015-02-26T22:14:48Z")
> [@aceplace57](#): > > I personally dislike Celsius because the number range is so tiny. 90 F is 32C 75F is 24C > > That tiny little change from 32 to 24C just doesn’t convey the difference in real life temperature. **90F is hot!** You’re sweating like a pig. 75F you’re loving life. Perfect weather. That wider scale makes it clear. You know its time for a windbreaker jacket if it’s 50F. 10C sounds like you need a heavy parka and scarf. The C scale ranges are just so odd. ??? As already said, it’s just what you’re used to. The important question is what the perceptible difference is in a one degree change in temperature. Is the difference between 24 and 25°C so great that a finer scale is needed? The practical answer is no, most people could barely tell the difference if moving from one temperature to the other, or possibly not at all. Canada went through an imperial to metric transition many years ago. I find metric temperatures harder to relate to than things like distance measures, probably because I have long-held fixed ideas about what specific Fahrenheit temperatures feel like. I actually have the digital thermometer in the car set to Fahrenheit because I prefer it, even though weather reports are always in Celsius, or what Dave Barry calls the “communist” system of measure. 😃 The peculiar schizophrenia here is with kitchen measures. Oven temperatures are almost always indicated in Fahrenheit, possibly because so many recipes either come from the US or are targeted for it. Food prices are even worse, they can be randomly quoted as per pound or per kg, or sometimes both at the same time, as in “Sale! Only $x per pound” but the actual products will be marked as dollars per kg. Or deli stuff will be marked as $x per 100 grams and I’ll ask for half a pound and have absolutely no idea what it will cost. ---
**Author:** ![iamthewalrus\_3](https://avatars.discourse-cdn.com/v4/letter/i/258eb7/32.png) [@iamthewalrus\_3](https://boards.straightdope.com/u/iamthewalrus_3)\ **Post date:** [February 26, 2015, 10:28pm UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/23 "2015-02-26T22:28:22Z")
I don’t think it’s that confusing to most people, but it is unintuitive, particularly with respect to temperature. I think a lot of people know that a kilogram is about 2 pounds, and a gallon is about 4 liters, and a meter is about 3 feet, and 10km is about 6 miles. The error on those is (almost) 10% or less, which is close enough for estimating. But with temperature, it’s harder because you can’t just multiply or divide, you have to also add or subtract, and you have to do the operations in a different order for each conversion (F to C: subtract, then divide, C to F: multiply, then add). Understanding why there’s a different order of operations is already straining the average person’s comfort with arithmetic. ---
**Author:** ![GreasyJack](https://avatars.discourse-cdn.com/v4/letter/g/df705f/32.png) [@GreasyJack](https://boards.straightdope.com/u/GreasyJack)\ **Post date:** [February 26, 2015, 10:33pm UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/24 "2015-02-26T22:33:02Z")
> [@wolfpup](#): > > The important question is what the perceptible difference is in a one degree change in temperature. Is the difference between 24 and 25°C so great that a finer scale is needed? The practical answer is no, most people could barely tell the difference if moving from one temperature to the other, or possibly not at all. I think the thing that really gets me with metric weather is that the “decades” don’t really make sense to me. I think with Fahrenheit you can say temperatures will be in the 40’s or 70’s or 90’s and that’s a close enough range of temperatures that you probably don’t have to change wardrobe from one end to the other. Whereas, say, 0 degree Celsius definitely requires an extra layer compared to 10 degrees. ---
**Author:** ![vd](https://avatars.discourse-cdn.com/v4/letter/v/b19c9b/32.png) [@vd](https://boards.straightdope.com/u/vd)\ **Post date:** [February 26, 2015, 10:36pm UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/25 "2015-02-26T22:36:50Z")
I grew up in California and then moved to Canada. If I am going to estimate the temperature based on how it feels, I will tend to go up to “about 20” before jumping to “about 70”. My first inclination will be that there is no temperature in between. ---
**Author:** ![TreacherousCretin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/treacherouscretin/32/476_2.png) [@TreacherousCretin](https://boards.straightdope.com/u/TreacherousCretin)\ **Post date:** [February 26, 2015, 11:16pm UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/26 "2015-02-26T23:16:18Z")
64 year old Amurkin here. I think metric is a far superior system, but have absolutely no feel for it. I’m hardwired to feel the way Dave Barry once put it: there’s metric, and there’s normal. ---
**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:** [February 27, 2015, 12:29am UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/27 "2015-02-27T00:29:34Z")
As always, there’s a [relevant XKCD](http://xkcd.com/526/). And the average American has a slightly better understanding of metric than of American units, but doesn’t realize it because their understanding of either system is so pathetically bad. ---
**Author:** ![SirRay](https://avatars.discourse-cdn.com/v4/letter/s/cc9497/32.png) [@SirRay](https://boards.straightdope.com/u/SirRay)\ **Post date:** [February 27, 2015, 12:33am UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/28 "2015-02-27T00:33:01Z")
If you are into woodworking, DIY, hobbies and models and so on - there are lots of things completely unintuitive within the Customary (aka FPS = Foot-Pound-Second) system - you just have to learn them (or, like everyone really does, use charts and gauges). Take small screw sizes - quick, what’s a #6 screw size? Yep, I had to look it up on my chart, it’s 0.138 inches dia. I know how the FPS sizes go (from #12 at least down to 000 - ok, there are number sizes above #12, but I haven’t worked with those), and I sort of know what the sizes are by sight. Metric’s a bit easier - M sizes by millimeter from M20 or about 3/4 inches (well, there’s bigger sizes of course) down to M1 (searching around, apparently it goes down to M0.6, probably smaller); still, need a gauge to verify both sizes…or do I? Metric ones you can just measure with a ruler (well, micrometer for the small ones), Number screws…gotta stick with the gauge. Small drill bits in the FPS system are numbers, with the largest normal size = 1 down to the smallest normal size of #80 (if you’re a model builder in the US, you quickly learn how small and brittle drill bits numbers 70 and **up** are). Metric drill bits again seems to be millimetre sized, like they should be. And finally my favorite bizarre DIY measurement - nails. I have boxes of nails in the basement, and they are measured as 6d or 8d common nails. **Penny** sizes :smack:. Checking Home Depot’s website, you can still buy nails in boxes marked in penny sizes. This sounds silly, why not give the sizes in inches anyway (6d = 2 inches, 8d = 2.5 inches) since you’ll get that off the chart. Well, the reason for this measuring system: > [@](#): > > The term penny nail originated in medieval times and is believed to describe the number of English pennies required to purchase 100 nails. > In the 15th century, 100 six-penny nails cost sixpence, 100 eight-penny nails cost eightpence, and so on, so that the larger the number, the longer the nail. Today, the term is used as a measurement of the length of a nail sold for wood applications. As can be readily seen, this measuring system is…rather obsolete and totally non-intuitive, seeing as how King Henry VIII no longer rules England (it even uses the old pence “d” symbol that the UK chucked in the 1970s). In the metric system, as it should be, nails are measured length by diameter in millimetres (similar to screws in the FPS system, which use dia x length in inches). Quite frankly, metrication of the small fastener industry would be rather a Godsent if they ever got around to doing it… ---
**Author:** ![penultima\_thule](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/penultima_thule/32/3833_2.png) [@penultima\_thule](https://boards.straightdope.com/u/penultima_thule)\ **Post date:** [February 27, 2015, 2:19am UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/29 "2015-02-27T02:19:15Z")
> [@Exapno\_Mapcase](#): > > If inches, pounds, and gallons were good enough for Jesus, they’re good enough for everybody. Would be a dodgy enough premise even if true, but wouldn’t JC have used Talmudic measures like spans, shekels and omer or something similarly archane? ---
**Author:** ![Kiwi\_Fruit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kiwi_fruit/32/12_2.png) [@Kiwi\_Fruit](https://boards.straightdope.com/u/Kiwi_Fruit)\ **Post date:** [February 27, 2015, 2:18am UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/30 "2015-02-27T02:18:53Z")
> [@chappachula](#): > > Here’s an easy way to convert temperatures: > Double the Celsius number , and add 30. > or , > Subtract 30 from the Fahrenheit number , then cut it in half. > > It’s quick and easy to do in your head, and accurate enough for most purposes… There are a couple of cool things about temperatures. 16 C = 61 F 28 C = 82F -40 C = -40 F Comfortable level in a room is about 22, warm is 25, hot is 30. Outside, put on a jersey is about 16, put on a jacket, about 10. I grew up with Imperial measurements and Fahrenheit temps and our country changed when I was in my late teens. We had stickers to put on the speedo for 50 km/h, (30 mph), 70 (43 mph) 80 (55 ish) and 100 (62 mph). As our previous speed limits were usually 30, 40, and 55, there wasn’t much difference. Distances on direction signs changed from miles with fractions to whole kilometres. So no more 10 1/2 miles sort of thing. Weights and measures were the biggest thing. No more pounds and ounces, stones and hundredweights. The main thing that people still struggle with is personal measures. If you grow up thinking you weigh 10 stone (140 lb) and are 5’ 8" then you tend to keep thinking that. But you are also 63.5 kg and 172 cm. A pound of butter is 454 gm, a pint of milk is 570 ml, except in the US where it’s 473 ml. There’s those darned different sized pints. 1 Imp pint = 20 fl oz, 1 US pint = 16 fl oz. ---
**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\ **Post date:** [February 27, 2015, 2:22am UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/31 "2015-02-27T02:22:40Z")
> [@friedo](#): > > Y’all are aware that every American child learns the metric system in school, right? > > Then they promptly forget it, like cursive. Probably because they can read the writing on the wall … 😃 ---
**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:** [February 27, 2015, 2:27am UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/32 "2015-02-27T02:27:20Z")
> [@SirRay](#): > > Take small screw sizes - quick, what’s a #6 screw size? Yep, I had to look it up on my chart, it’s 0.138 inches dia. Actually, this is a great example of the value of traditional measures that we’re familiar with. I can picture exactly what a #6 screw size is, or a #8, and the kinds of things I might use them for. “0.138 inches diameter” means nothing to me. ---
**Author:** ![Askance](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/askance/32/8281_2.png) [@Askance](https://boards.straightdope.com/u/Askance)\ **Post date:** [February 27, 2015, 3:16am UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/33 "2015-02-27T03:16:18Z")
> [@GreasyJack](#): > > I think the thing that really gets me with metric weather is that the “decades” don’t really make sense to me. I think with Fahrenheit you can say temperatures will be in the 40’s or 70’s or 90’s and that’s a close enough range of temperatures that you probably don’t have to change wardrobe from one end to the other. Whereas, say, 0 degree Celsius definitely requires an extra layer compared to 10 degrees. It might help that few populated areas in Australia ever get that low, but there was a nice mnemonic put about for higher ranges when we were converting: The Tingling Teens The Temperate 20s The Thirsty 30s The Flaming 40s That’s the kind of thing that’s needed, IMO; easily accessible markers that people get. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [February 27, 2015, 3:26am UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/34 "2015-02-27T03:26:47Z")
> [@friedo](#): > > Y’all are aware that every American child learns the metric system in school, right? > > Then they promptly forget it, like cursive. Well, unless they become drug dealers. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [February 27, 2015, 3:25am UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/35 "2015-02-27T03:25:06Z")
> [@Exapno\_Mapcase](#): > > If inches, pounds, and gallons were good enough for Jesus, they’re good enough for everybody. Jesus of Nazareth, if he existed, probably worked in spans, hins, and shekels. A base 10 system of measurement units makes sense in doing computation using a base 10 numbering convention such as the Indo-Arabic convention insofar as differences of scale can be handled with exponents (and thus treated with logarithms to limit the propagation of rounding errors). A system with a base of 2 or factors of 2 (such as base 8 or base 16) is very convention for binary computation, but can become clunky for manual calculations. The SI (“Metric”) system is entirely intuitive if you spend a modicum of time working in it rather than trying to rationalize conversions from the almost nonsensical Customary system of units, and the arguments against (such as that Celcius increments are too coarse–show me someone who can distinguish between 71°F and 73°F) are uninformed at best. Unfortunately, because so many engineering materials and connectors used in the United States are fundamentally based on SAE unit standards, making the transition to SI, even when it would be fiscally and logistically reasonable (e.g. would allow commonality with worldwide supply chains and simplify homologation with standards of the rest of the world) the impetus to change and the cost in terms of maintaining legacy systems makes it unlikely that the switch will every occur. Stranger ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [February 27, 2015, 3:33am UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/36 "2015-02-27T03:33:08Z")
Error ---
**Author:** ![boffking](https://avatars.discourse-cdn.com/v4/letter/b/858c86/32.png) [@boffking](https://boards.straightdope.com/u/boffking)\ **Post date:** [February 27, 2015, 3:43am UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/37 "2015-02-27T03:43:13Z")
> [@Chronos](#): > > As always, there’s a [relevant XKCD](http://xkcd.com/526/). > > And the average American has a slightly better understanding of metric than of American units, but doesn’t realize it because their understanding of either system is so pathetically bad. Since when does a 2 liter bottle hold **3** liters? ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [February 27, 2015, 5:49am UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/38 "2015-02-27T05:49:29Z")
Yeah, Canada is a good example. I grew up with Imperial, and then switched to metric before Trudeau I got the boot. By then, it was ingrained in the economy. I still think in gallons and miles, although I can convert back and forth. a Litre is a quart (3.8L to the phony gallon, 4.5L to the real gallon that nobody uses any more.) So when I fill the car in gallons during a sojourn south, I divide the gallonage by 4. Miles? 100km=60mi (actually, 62.5mi). So if you have a kilometrage to convert - distance or speed - strip off the last digit and multiply by 6 - i.e. 70km/hr - 7x6=42mph (actually, 43); going the reverse, divide by 6, multiply by 10; 55mph, 6x **9** =54 so a tich over 90kph For temperatures - I’ve been using Celluloid exclusively for so long, I have to stop and think sometimes. Someone one generation younger knows nothing of real degrees, only C. (but even they talk feet and inches, familiar with one-foot rulers from school) Simple calculation for weather - 68F = 20C is a cool room temperature. Each 9F is 5C so 10:5 is a close enough approximation. 32F = 0C estimate from there 40F to 5C 50F to 10C 60F to 15C 80F to 25C Actually, here’s where it starts to slip - 25C is actually 77F, 30C - 86F; but you get the picture - the 20’s are warm, the 30’s are hot, and 40C = 104F and above is freakin’ hot. As for litres and kilograms and food - who cares unless you cook? People work with portions, and pick the nearest round-number size - one cup, or 300ml instead of 288. We still use cup measures and teaspoons; similarly construction is still in feet and inches because (a) too much trouble to change and no need and (b) big American market south of us wont take different sizes. But as a counterpoint, I understand the entire US auto industry is in metric for compatibility with foreign markets. It goes both ways. ---
**Author:** ![Critical1](https://avatars.discourse-cdn.com/v4/letter/c/3e96dc/32.png) [@Critical1](https://boards.straightdope.com/u/Critical1)\ **Post date:** [February 27, 2015, 6:07am UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/39 "2015-02-27T06:07:20Z")
Sounds like a golden opportunity, We could come up with a new system, call it Murikan. Its the metric system but for temperatures we use 0M as freezing and 200M as boiling. It just might work! ---
**Author:** ![Spectre\_of\_Pithecanthropus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spectre_of_pithecanthropus/32/12343_2.png) [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)\ **Post date:** [February 27, 2015, 9:11am UTC](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698/40 "2015-02-27T09:11:37Z")
Speaking for myself, it’s simple enough to convert one unit into another, like pounds to kilograms. But converting mpg to kpl is trickier. Well, of course I can do it, but I can’t readily estimate it. I have to do the arithmetic. [Previous page](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698.md?page=1) [Next page](https://boards.straightdope.com/t/how-confusing-unintuitive-is-the-metric-system-to-the-average-american/713698.md?page=3)