# Why we need the metric system **URL:** \ **Category:** In My Humble Opinion\ **Created:** [September 17, 2010, 10:28pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140 "2010-09-17T22:28:19Z")\ **Posts on this page:** 20\ **Page:** 4
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [September 20, 2010, 5:50am UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/61 "2010-09-20T05:50:23Z")
Is that imperial lightyear or survey lightyear? ---
**Author:** ![Mogle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mogle/32/12021_2.png) [@Mogle](https://boards.straightdope.com/u/Mogle)\ **Post date:** [September 20, 2010, 7:27am UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/62 "2010-09-20T07:27:08Z")
> [@tracer](#): > > Huh. I’ll be darned. The pound-force article on Wikipedia confirms it: The pound of force is defined as the weight of one pound of mass at the surface of the Earth, and not the other way around. It makes sense when you think about it, defining a unit of mass pretty easy, all you need to do take a lump of metal and say ‘from now on this one kg/pound/slug/whatever’. But force? How would you define a unit of force without referring to a unit of mass? ---
**Author:** ![footballisplayedwithyourfeet](https://avatars.discourse-cdn.com/v4/letter/f/9f8e36/32.png) [@footballisplayedwithyourfeet](https://boards.straightdope.com/u/footballisplayedwithyourfeet)\ **Post date:** [September 20, 2010, 8:46am UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/63 "2010-09-20T08:46:44Z")
> [@Martini\_Enfield](#): > > > [@sisu](#): > > > > In Australia metric came in the year I was born. I am one of those people who love metric for calculations, I can do it in my head but still use it say someone is 6’2" etc. > > > > Funny but I know how tall a 6’ person is in my head but struggle with 180cms. > > Also interestingly, despite the fact distances (and speeds thereof) are done in metric (MM, C, Km, Km/h etc) TV screens and computers are still sold with inches and most people I know- even younger people- still use feet and inches for a person’s height. Here in Europe we also use inches for tv’s. I really don’t remember when this started exactly, but at some point they switched from cm to inches. ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [September 20, 2010, 4:29pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/64 "2010-09-20T16:29:16Z")
> [@footballisplayedwithyourfeet](#): > > Here in Europe we also use inches for tv’s. I really don’t remember when this started exactly, but at some point they switched from cm to inches. This has _got_ to be one of the signs of the apocalypse. We’ll be switching to cubits next… ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [September 20, 2010, 6:21pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/65 "2010-09-20T18:21:25Z")
> [@tracer](#): > > > [@Mangetout](#): > > > > The same calculations on a measurement of 4 foot 7 will require an intermediate step of conversion into a single unit and perhaps another step converting the single-unit answer back into feet and inches. > > … which the British had to put up with with their currency system for a long time, too. (1000 pence was “4 pounds, 3 shillings, 4 pence” or “4 pounds 3 and 4” until the decimalification of British currency in, what was it, the 1970s?) Yes. in 1971, British currency became sane - 100 ‘New Pence’ to a pound. In 1981, the ‘New’ prefix was dropped, when they weren’t really new any more. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [September 21, 2010, 12:19am UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/66 "2010-09-21T00:19:09Z")
> [@Balthisar](#): > > The US is already metric. All of these metric proposals are aimed at getting everyday folk to use the metric system, for which there \*are[i/] advantages, but not any advantages to people that cause them to switch of their own free will. As in economics, it’s all about incentives, and there just no incentive for normal, everyday people to switch. > > Business is obviously influenced by incentives, and everywhere that it matters (i.e., economically), we’re already metric. Yeah, but, I don’t think we are. That is, in many ways we are, but a machine shop in the US is typically somewhere between 100% English and dual versions of every tool that has a size (drills, taps, reamers, collets, punches, and the like). I hear that in Europe the machine shops have only one version of sized items, and never have to make adapters or stock twice as many fasteners. Way simpler! I also often buy instruments that are in some way optimized for English units (for example a transducer goes from 0 to 10 volts with 0 to 10 psi pressure input). Pressure gages, flowmeters, force gages, and similar things are generally made in two separate product lines, English and SI. And it is still pretty typical for a hardware store to have a big selection of “normal” fasteners like 1/4-20 nuts, and then a limited selection of nuts that are “special”, such as acorn nuts, and nylon locking nuts, and jam nuts, and castellated nuts, and metric nuts, like being metric is obscure. ---
**Author:** ![dzero](https://avatars.discourse-cdn.com/v4/letter/d/5f9b8f/32.png) [@dzero](https://boards.straightdope.com/u/dzero)\ **Post date:** [September 21, 2010, 12:55am UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/67 "2010-09-21T00:55:25Z")
> [@tracer](#): > > > [@footballisplayedwithyourfeet](#): > > > > Here in Europe we also use inches for tv’s. I really don’t remember when this started exactly, but at some point they switched from cm to inches. > > This has _got_ to be one of the signs of the apocalypse. > > We’ll be switching to cubits next… They left that one out of the sacred text that is “Ghostbusters”, but it sounds legit [source](http://www.imdb.com/title/tt0087332/quotes?qt0475882) > [@](#): > > **[Dr. Peter Venkman](http://www.imdb.com/name/nm0000195/)**: This city is headed for a disaster of biblical proportions. > **[Mayor](http://www.imdb.com/name/nm0546868/)**: What do you mean, “biblical”? > **[Dr Ray Stantz](http://www.imdb.com/name/nm0000101/)**: What he means is Old Testament, Mr. Mayor, real wrath of God type stuff. > **[Dr. Peter Venkman](http://www.imdb.com/name/nm0000195/)**: Exactly. > **[Dr Ray Stantz](http://www.imdb.com/name/nm0000101/)**: Fire and brimstone coming down from the skies! Rivers and seas boiling! > **[Dr. Egon Spengler](http://www.imdb.com/name/nm0000601/)**: Forty years of darkness! Earthquakes, volcanoes… > **[Winston Zeddemore](http://www.imdb.com/name/nm0001368/)**: The dead rising from the grave! > **[Dr. Peter Venkman](http://www.imdb.com/name/nm0000195/)**: Human sacrifice, dogs and cats living together… mass hysteria! ---
**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:** [September 21, 2010, 1:44pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/68 "2010-09-21T13:44:31Z")
> [@Napier](#): > > Yeah, but, I don’t think we are. That is, in many ways we are, but a machine shop in the US is typically somewhere between 100% English and dual versions of every tool that has a size (drills, taps, reamers, collets, punches, and the like). I hear that in Europe the machine shops have only one version of sized items, and never have to make adapters or stock twice as many fasteners. Way simpler! While that’s true, there are two things to consider: (1) legacy applications, and (2) commercial advantage. In the case of (1), Canada, for example has been metric since the 70’s, but yet they still have so much legacy use that they’ll never really shake the metric system. The machine shops that I’ve been to there still have to support both metrics anyway. For (2), I’m often a commercial consumer of machine shop services (my company is nearly 100% SI), and I don’t really care what the machine shop does internally as long as they’re able to compete, i.e., give me what I need on time and on budget. > [@](#): > > I also often buy instruments that are in some way optimized for English units (for example a transducer goes from 0 to 10 volts with 0 to 10 psi pressure input). Pressure gages, flowmeters, force gages, and similar things are generally made in two separate product lines, English and SI. And it is still pretty typical for a hardware store to have a big selection of “normal” fasteners like 1/4-20 nuts, and then a limited selection of nuts that are “special”, such as acorn nuts, and nylon locking nuts, and jam nuts, and castellated nuts, and metric nuts, like being metric is obscure. Remember how I said my company was “nearly” 100% SI? Yeah, our tooling is all metric, and our products are all metric, but a lot of our gages are still US (yeah, even in Canada and Mexico). We’re getting a lot better, but even I have some resistance to leaving behind psi and pounds-force. And that’s not because I can’t deal in newtons, but for my entire career I’ve known that I need _x_ pounds for _y_ thickness, for example. ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [September 21, 2010, 2:02pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/69 "2010-09-21T14:02:03Z")
I had forgotten about things like “number 8 wood screws”, which use neither U.S. customary units nor metric (S.I.) units. They’re kinda like dress sizes, I guess. Although there’s a hell of a lot more standardization in wood-screw sizes than there is in dress sizes. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [September 21, 2010, 2:36pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/70 "2010-09-21T14:36:16Z")
> [@Max\_the\_Immortal](#): > > Do people really make this mistake? I figure most people would understand that “301 ºC minus 300 ºC” would translate to “574.15 K minus 300 K”. It’s a temperature level minus a number of temperature units, not a temperature level minus another temperature level. [Newspapers do](http://www.independent.co.uk/environment/wilting-in-the-heat-the-woodlands-in-desperate--need-of-foreign-implants-578894.html), from time to time: > [@](#): > > Only these heat-resistant trees can cope with the rigours of climate change that could see temperatures rise by 5C (41F) this century. 😛 ---
**Author:** ![Apollyon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/apollyon/32/4238_2.png) [@Apollyon](https://boards.straightdope.com/u/Apollyon)\ **Post date:** [September 21, 2010, 9:43pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/71 "2010-09-21T21:43:24Z")
> [@Sunspace](#): > > > [@Apollyon](#): > > > > Well, I don’t _mind_ the idea of buying my fruit juice in cubic meters.. but […] that’s going to weigh like 158 stone or something… 🙂 > > 1 cubic metre of water (or fruit juice, which is mostly water) = 1000 kg (1 tonne)! Easy-peasy! I need that Simpsons “That’s the Joke” picture. 😃 NZ has been metric since the early 70s – when I was a kid – and I use metric for everything… well except some people’s heights… and see nothing wrong with being 6’ 4" and 118 kg… well, nothing wrong other than being overweight. 🙂 My son, on the other hand, is currently about 140 cm… I must be finally getting the hang of this metric thing. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [September 22, 2010, 1:20am UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/72 "2010-09-22T01:20:51Z")
> [@Balthisar](#): > > I’m often a commercial consumer of machine shop services (my company is nearly 100% SI), and I don’t really care what the machine shop does internally as long as they’re able to compete, i.e., give me what I need on time and on budget. All well and good for you, but it’s a pain for the machine shop. Besides, the only resources they can bring to bear on all that extra hassle and expense are the prices they charge and the service they provide. To some degree the choice of units is arbitrary, especially if you don’t use any math that relies on the coherence of unit systems (that property that makes many equations require no constant parameters, like F=m•a, in coherent systems like the SI). What isn’t arbitrary, and what is arguably the only wrong way to go about doing it, is to maintain multiple unit systems. It COSTS. ---
**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:** [September 22, 2010, 4:02pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/73 "2010-09-22T16:02:43Z")
> [@Napier](#): > > > [@Balthisar](#): > > > > I’m often a commercial consumer of machine shop services (my company is nearly 100% SI), and I don’t really care what the machine shop does internally as long as they’re able to compete, i.e., give me what I need on time and on budget. > > All well and good for you, but it’s a pain for the machine shop. Besides, the only resources they can bring to bear on all that extra hassle and expense are the prices they charge and the service they provide. > … > What isn’t arbitrary, and what is arguably the only wrong way to go about doing it, is to maintain multiple unit systems. It COSTS. Yeah, maybe it costs, but there are worse costs. Maybe the machine shop can decide they’re not going to do any SI work, and make things cheaper for them. The new cost is the loss of all of the SI work. Or maybe they want to be pioneering, and make a purely emotional, non-logical decision to be _exclusively_ an SI shop. That will have a huge cost in the loss of US units work. It’s an economic decision, pure and simple. Their competition has to make the same decisions. The fact that there is competition will _limit_ the costs associated with both systems. Not until the incentives for going 100% SI are greater than costs will anyone switch. There simply aren’t enough incentives for a switch. It won’t do anyone any good that hasn’t discovered the incentives already for himself, and has already switched. Saying “let’s post speed limits in kilometers” doesn’t serve anyone except for sign makers and post hole diggers. ---
**Author:** ![Floater](https://avatars.discourse-cdn.com/v4/letter/f/dc4da7/32.png) [@Floater](https://boards.straightdope.com/u/Floater)\ **Post date:** [September 22, 2010, 4:25pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/74 "2010-09-22T16:25:07Z")
> [@tracer](#): > > Most metric-speaking countries use liters (instead of cubic meters) In Sweden we use cubic metres when buying heating oilf for our houses. > [@footballisplayedwithyourfeet](#): > > Here in Europe we also use inches for tv’s. I really don’t remember when this started exactly, but at some point they switched from cm to inches. As far as I know we have never used centimetres. It’s always been inches. ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [September 22, 2010, 4:25pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/75 "2010-09-22T16:25:31Z")
> [@tracer](#): > > I’ve just put together a video describing one (often overlooked) reason why we Americans need the metric system – and, no, this reason ISN’T the Mars Climate Orbiter: > > [http://www.youtube.com/watch?v=KtNnVvdvfZw](http://www.youtube.com/watch?v=KtNnVvdvfZw) **UPDATE:** I’ve uploaded a higher-quality version of this video to YouTube, with easier-to-read text in the graphics and balanced audio. It’s here: [![](https://img.youtube.com/vi/XI9w8g4UT2I/maxresdefault.jpg "Why we need the metric system") ](https://www.youtube.com/watch?v=XI9w8g4UT2I) As a result, I have **DELETED** the original video link I posed in the OP. Please use the new link to watch this video instead. ---
**Author:** ![Gymnopithys](https://avatars.discourse-cdn.com/v4/letter/g/fbc32d/32.png) [@Gymnopithys](https://boards.straightdope.com/u/Gymnopithys)\ **Post date:** [September 22, 2010, 5:08pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/76 "2010-09-22T17:08:51Z")
> [@Floater](#): > > > [@tracer](#): > > > > Most metric-speaking countries use liters (instead of cubic meters) > > In Sweden we use cubic metres when buying heating oilf for our houses. > > > [@footballisplayedwithyourfeet](#): > > > > Here in Europe we also use inches for tv’s. I really don’t remember when this started exactly, but at some point they switched from cm to inches. > > As far as I know we have never used centimetres. It’s always been inches. In Switzerland they still use inches for garden hoses and plumbing pipes from times immemorial :rolleyes: ---
**Author:** ![justdoit](https://avatars.discourse-cdn.com/v4/letter/j/e56c9b/32.png) [@justdoit](https://boards.straightdope.com/u/justdoit)\ **Post date:** [September 7, 2025, 1:59am UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/77 "2025-09-07T01:59:58Z")
Funny SNL skit about it: [https://www.youtube.com/watch?v=JYqfVE-fykk](https://www.youtube.com/watch?v=JYqfVE-fykk) ---
**Author:** ![mixdenny](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mixdenny/32/2962_2.png) [@mixdenny](https://boards.straightdope.com/u/mixdenny)\ **Post date:** [September 7, 2025, 4:06pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/78 "2025-09-07T16:06:36Z")
Referring all the way back to the OP - Troy pounds are a thing in the silver collecting world. A Troy pound bar is worth about $1800 now. ---
**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:** [September 7, 2025, 4:52pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/79 "2025-09-07T16:52:52Z")
> [@Napier](#): > > 301 ºC minus 300 ºC is 1 ºC? But that is almost frozen, and we were talking about something hot! I don’t see how kelvin fixes that. You could just as well say “574 K minus 573 K is 1 K. But that’s liquid helium temperature, and we were talking about something hot!”. Kelvin definitely matters when you’re multiplying or dividing temperatures, but when you’re subtracting them, the Celsius (or Fahrenheit) offset goes away anyway. Meanwhile, for all that people talk about the powers-of-ten thing, that’s only like #4 on the list of why metric is better than the “customary system”. The complaint in the OP’s video, that so many different units have the same name, is #1. And it’s not a problem until it is, which does happen sometimes, and then it’s a huge problem. ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [September 7, 2025, 6:06pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/80 "2025-09-07T18:06:18Z")
Celsius is vastly overrated compared to Fahrenheit. Also square/cubic foot is better than square/cubic meter. Other than that the metric system is superior. [Previous page](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140.md?page=3) [Next page](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140.md?page=5)