What’s So Bad About The Imperial System Anyway?

As a Hackaday writer, you can never predict where the comments of your posts will go. Some posts seem to be ignored, while others have a good steady stream of useful feedback. But sometimes the comment threads just explode, heading off into seemingly uncharted territory only tangentially related to the original post.

Such was the case with [Steven Dufresne]’s recent post about decimal time, where the comments quickly became a heated debate about the relative merits of metric and imperial units. As I read the thread, I recalled any of the numerous and similarly tangential comments on various reddit threads bashing the imperial system, and decided that enough was enough. I find the hate for the imperial system largely unfounded, and so I want to rise to its defense.

Did you measure that room in 'feet', or in 'flip-flops'?
Did you measure that room in ‘feet’, or in ‘flip-flops’?

What is a system of units anyway? At its heart, is just a way to measure the world. I could very easily measure the length and width of a room using my feet, toe to heel. Most of us have probably done just that at some point, and despite the inconvenient and potentially painful problem of dealing with fractionalization of your lower appendage, it’s a totally valid if somewhat imprecise method. You could easily pace out the length of the room and replicate that measurement to cut a piece of carpet, for instance. It’s not even that much of a stretch to got to the home center and buy carpet off the roll using your personal units — you might get some strange looks, but you’ll have your personal measuring stick right with you.

The trouble comes when you try to relate your units to someone not in possession of your feet. Try to order carpet online and you’ll run into trouble. So above and beyond simply giving us the tools to measure the world, systems of units need to be standardized so that everyone is measuring the same thing. Expanding trade beyond the dominion where one could refer to the length of the king’s arm and have that make sense to the other party was a big driver of the imperial system first, and then the metric system. And it appears to be one of the big beefs people have regarding the United States’ stubborn insistence on sticking with our feet, gallons, and bushels.

How Ridiculous are We Talking?

quote-definition-of-a-meterThe argument that imperial units are based on ridiculous things like the aforementioned king’s arm? That’s not an argument when a meter was originally defined as one 10-millionth of the distance from the north pole to the equator. Even rigorously defined relative to the speed of light or the wavelength of krypton-86 emissions in a vacuum, the meter is based on phenomena that are completely inaccessible to the people who will use is, and unrelated to their daily lives. At least everyone has seen a foot that’s about a foot long.

Doing the conversions between imperial units and SI units is tedious and error prone, they say. Really? Perhaps I’d buy that argument a hundred years ago, or even fifty. But with pervasive technology that can handle millions of mathematical operations a second, there’s not much meat on that bone. I’ll grant you that it’s an extra step that wouldn’t be needed if everyone were on the same system, and that it could lead to rounding errors that would add up to quite a bit of money over lots of transactions. But even then, why is that not seen as an opportunity? Look at financial markets — billions are made every day on the “slop” in currency exchanges. I find it unlikely that someone hasn’t found a way to make money off unit conversions too.

Another point of contention I often see is that imperial units make no sense. Yes, it’s true that we have funny units like gills and hogshead and rods and chains. But so what? Most of the imperial system boils down to a few commonly used units, like feet and gallons and pounds, while the odder units that once supported specialized trades — surveyors had their rods and chains, apothecaries had their drams and grains — are largely deprecated from daily life now.

Deal with It

For the units that remain in common use, the complaint I hear frequently is, “Why should I be forced to remember that there are 5,280 feet in a statute mile? And why is there a different nautical mile? Why are there 12 inches in a foot anyway? A gallon has four quarts, why does that make sense?” And so on. My snappy retort to that is, again, “So what?” If you’re not a daily user of the imperial system, then don’t bother yourself with it. Stick to metric — we don’t care.

If you’re metrified and you’re forced to use imperial units for some reason, then do what a lot of us imperials have to do — deal with it. I’m a scientist by training, and therefore completely comfortable with the SI system. When I did bench work I had to sling around grams, liters, and meters daily. And when I drove home I saw (and largely obeyed) the speed limit signs posted in miles per hour. No problems, no awkward roadside conversations with a police officer explaining that I was still thinking in metric and thought that the 88 on my speedometer was really in km/h and I was really doing 55. If I stopped at the store to pick up a gallon of milk and a couple of pounds of ground beef for dinner, I wasn’t confused, even if I slipped a 2-liter bottle of soda into the order.

At the end of the day, I don’t really see what all the fuss is about. Imperial and metric both have their place, and each system seems to be doing its job just fine. If your argument is that imperial units are inelegant and awkward, even though you’re correct I don’t think that’s enough to sway the imperial holdouts. And if you’re just upset because we’re being stubborn and won’t join the enlightened metric masses, then I think you’re probably going to be upset for a long time to come.

890 thoughts on “What’s So Bad About The Imperial System Anyway?

  1. I use a binary watch (hours/minutes) and have thought all the muggles would be better off switching to a binary-friendly division of time.
    64min/hour 64second/min etc.
    However the bits do roughly line up with conventions 100 000 ~= half-past, 010 000 ~= quarter after, etc.

  2. You’re right with “0.3048 times the length of the path travelled by light in vacuum during a time interval of 1/299792458 of a second.” the definition of the foot is so much better

    1. The whole world is metric and just uses it to measure everything from things in the home, the market and the job. They don’t bother themselves with the definition of the metric. That is for the managers of the system to deal with. What is real important is that the metre and all of the other units are consistent world-wide and they are.

  3. >”the meter is based on phenomena that are completely inaccessible to the people who will use is, and unrelated to their daily lives”

    That’s not true. The very original definition of the meter was the seconds pendulum, which is a string and a hanging weight that makes a half-cycle in one second. They also realized that for the same reasons why the pendulum worked, the average adult human stride lenght (left-right step) is approximately a meter so they figured it would be a good unit to pace distances.

    The seconds pendulum is a device that can be built by anyone to within 1% accuracy with ease. Knowing your exact latitude on the earth’s surface, you can refine the measurement further.

    Everything that came after that were attempts at fixing the meter down more precisely, but the old definitions are still useful.

    1. The historical records of the seconds pendulum – of course depending on where it is measured – returns a length of 997 mm compared to the meter defined as 10 millionth part of the prime meridian. I don’t know whether that’s a coincidence, or a deeper physical connection between the force of gravity and the size of the Earth.

      In any case, you don’t need to measure the whole distance from the equator to the pole – you can measure the difference in angle to a distant star between two points on the earth, and get your north-south difference in latitude and therefore your distance in meters. Then it’s just a matter of breaking it down to smaller bits. Any surveyor, ship navigator, etc. would know how to do that, so the meter could be independently verified to a reasonable accuracy everywhere.

      That meant your kilogram and liter were reasonably consistent across vast distances without the need to obtain and maintain a standard prototype, like what happened between the British and the American foot standard where it was found one wore down and became shorter. The standard measures between the colonies started to drift apart and there were something like 52 different inches in use across the world because they just couldn’t keep the prototype objects the same.

  4. So why do all the metric fanFolks still use base 12 to tell time. And why I’m at it, why do some countries allow or even require us to drive on the wrong side of the road. sigh …

    1. Because the SI MKS system is based on the second, and 86400 seconds a day aligns better with hours and minutes. If you want decimal time, you have to change the second or it will be awkward. If you change the second, then you have to change the entire system of units.

  5. Would you all like to know what one of the best parts about the imperial system is? I hope you do because I’m telling you anyway.

    JOB SECURITY. We crazy Americans are taught to work with the system of measure we use here in our country. Conveniently, anyone with some sort of formal scientific training is also taught the “glorious” metric system. We are comfortable with both. On the other hand, all of you metric purists just disqualified yourself from a good Civil Engineering job because you can be bothered to learn a new bit of information, or use a conversion table.

    The imperial system keeps American jobs in American hands, and makes Americans more desirable employees for any company that intends to do business in the USA. So please, keep to your imperial system. It’s funny that the same people who always seem to be encouraging others to learn a several languages (instead of advocating that we change so that everyone speaks the same one) are the same people who can’t be bothered to use a different system of measurement. If Y’all want to learn to adopt English and the metric system as Earth’s universal systems, great, less work for me, but until then, do what the rest of us do and “learn another language”.

    1. I think that might be the root of the problem here.
      I will say from the start; the Imperial system is fully functional and usable. There is no reason or flaw that keeps it from being sufficient for any task it was originally created for.
      Yes, conversions are an inconvenience, but it is not impossible, and capable people work in both regularly.

      The several-hundred-country question though, is why there is so much resistance to change when there is a “better” alternative that is also well defined.
      Most of the US already uses or is aware of it already, and the US switching to metric would eliminate the issue of conversion tables and miscommunication altogether.

      There are valid reasons to switch to metric, but most of the reasons to stay imperial don’t make as much sense to the rest of the world.
      Nationalism, apparent job security, or stubbornness aren’t very good reasons to keep a system which you originally got from the British, and the rest of the developed world has or is migrating away from.

      1. I’m sure it would cost us (the U.S.) nothing to convert completely (note that we use metric for a whole lottta stuff), so how about you just don’t use American crap if you don’t like our measurements?

        That’s the attitude we got back in the 70s, when import cars became a big thing. Take our metric Toyotas and Volkswagens, or leave them. It was the first time we were give a put-up-or-shut-up ultimatum regarding systems of measurement. You know what most of us did? We bought metric tools. Problem solved.

        Back to you.

    2. Really? Is that why since the failure of the US to complete metrication in the ’70s, millions of jobs have fled the US for metric countries and metric products are flooding into the US. The US doesn’t actually use imperial, it is illegal. The US uses US Customary or USC. The two are not the same. Imperial was a reform on the older English units that the US refused to adopt in 1824.

      The US doesn’t even use USC universally. 60 % of remnant American industry, such as automobiles and heavy machinery to name as few are fully metric. The rest are hybrid. Only in the US is everyone required to own a dual set of tools, one for obsolete products and another for metric products. This adds a cost burden and a major source of mistakes when two components different only in their roundness to a particular unit are mixed.

      If you want ot be different, fine, but pay the price.

  6. I will never forget what an America Business Woman once said, “We have to convert all the measurements into normal units so that we can build them.”
    No, my dear, you converting Normal units into obscure units just so your old boys can build a new car.

  7. The “my arbitrary system of measurement is better than yours” is a seriously annoying thing people like to bring up.
    I do a lot of design in US Customary. I can estimate a foot and a yard and so on reasonably well enough. I have other things that use metric, estimating a meter is easy enough.
    I don’t know why so many people get so bothered by “use what you’re used to”. It’s not like one is objectively superior to another, they both measure something and give an answer that is repeatable for how big it is.

  8. I do a bit of machining, and have always found that imperial is a hassle. My vernier caliper’s imperial scale is in 128ths of an inch, and my milling machine and lathe are in 1000ths. Metric screws are pretty simple, diameter and pitch. Can anyone tell me off the top of their head how big a #8×32 machine screw is in mil, or fractional inches?

    When you want to calculate volumes, Imperial sucks. How many cubic inches in a cubic foot. 1728. How many cubic inches in a Gallon? Is that a us gallon, or imperial gallon. Try smaller volumes sometimes, yuck.

    Additionally, it’s not a matter of just deciding a system and sticking with it, there’s often outside influences. Here in Canada where we’re officially metric, Almost all of the hardware in stores is imperial. Down at the Home Despot I can buy a box of 16 #10×32 screws for $3, or I can buy a single M5 screw of similar length for $.49 (if it’s even stocked)

      1. Yes you would, because the metric ones almost universally come with a button that converts to 1/1000 inches or has a second scale in the same. I haven’t found a single exclusively metric vernier caliper, because metric folks have to deal with parts in imperial all the time – thanks to car parts and electronics often being in US customary units.

        Especially thanks to the electronics being standardized on the inch, it’s possible to live your life in the US without ever needing more than a metric wrench set for those odd import cars, whereas in all the other countries you bump into imperial measures all the time and that pisses people off.

          1. Same difference. I have not seen a manual metric vernier caliper that didn’t have mils/thous on the side. It seems you have to go to Japan if you want to buy an exclusively metric caliper.

          1. Except that the same caliper has metric, which I can use on any metric machine, or imperial, which can’t be used on any imperial machine.

            I have calipers that work in mil as well, of course, but you can’t put them on even ground when the standard units in metric are all easily convertable (factors of 10). Obviously people thought this was useful, because they started doing things (like machining) in decimal inches. Now, having things standardized near fractions, but expressed in decimal leads to a bunch of weird sizes, like .063″ sheet, etc.

            It’s a mess. Yes, we can all manage it, but it would work better if we weren’t tied to it.

          2. Again what is the cost effective choice here? Buy a new caliper or buy a new machine. Look, everyone agrees it would be best if there was one system, and given its penetration, metric is the best one, but please PLEASE don’t give me this hollow argument about it being intrinsically superior, because it is not, but do consider the hidden costs of converting the U.S. past the superficial level. The old systems are dug in and we are going to have to live with them for as long as most people reading this thread will be alive – whining about it isn’t going to make this go away. Hell even the French have sectors that haven’t fully converted.

        1. I don’t know what century you live in but the auto industry went metric in the ’70s. There is only metric machining for auto parts. Electronic parts switched to metric footprints in the ’90s. All of your surface mount components today are metric. The reason is that when the electronics industry fled the US for Asia, the Asians refused to use USC and pushed for metric fully.

          The Americans are the most pissed off as they have to constantly deal with dual and hybrid products and tooling. The remnant of American engineering and manufacturing is a constant source of errors and down time when parts don’t fit together because one is metric and the other isn’t.

          You can buy if most markets metric only digital verniers. If the manufacturers decide to produce a dual set as standard it is to cover all markets. Outside the US if the vernier has a switch to go to inches, no one uses it. They use metric only as that is all they understand. Americans are the ones that are whining about encountering metric, the rest of the world just ignores inches

          1. I think you’re conflating “vernier” with “caliper”. Vernier refers to a type of mechanical scale used to get an additional digit of precision from a reading. https://en.wikipedia.org/wiki/Vernier_scale Calipers with vernier scales can be calibrated in two units of measure by using the opposite edge of the scale for the second unit. Digital calipers are a whole different thing.

      2. But at least as a system with metric you don’t have mixes of fractional and decimal units.
        If I had a metric machine then any metric caliper is going to give me measurements I can use without conversions.

        I would if it was available, but all of the machine tools available locally are in mil.

        1. This is a huge problem. Americans have USC forced down their throat when young and only learn fractional inches. Then if they go into industry, what industry is left, they find fractions don’t work and have to use decimals. But decimals and fractions are not mutually comprehensible and a struggle results, usually in costly errors. Working in decimals sometimes and fractions other times or at the same time is confusing. Only in American shops will you find charts by every machinists work area to convert decimal to fractions and millimetres.

          Machine tools built since the ’70s are dual and can be switched either by a button or by code. Yours must be much older. All of the electronic machine tools operate metric internally. The encoders and resolvers and even the ball screws are metric. When you work in metric, everything is direct, when you work in USC it is a constant back and forth conversion going on internally. This creates some loss of precision when dealing with inch machining. Of course if it is in inches it won’t be that precise to begin with.

          1. Oh, for crying out loud. Really? “But decimals and fractions are not mutually comprehensible and a struggle results, usually in costly errors.” Somebody says I need that 5-7/64″ long, I instantly go to my calculator, hit 7 ÷ 64 = + 5 = , and my calculator tells me 5.109375. I round this to 5.109 because obviously if somebody’s specifying something in fractions he doesn’t need it closer than a mil. Nobody can force you to work in fractions. This is not (mumble mumble Mars Climate Orbiter mumble mumble) rocket science.

    1. Actually I’ve got some old ass verniers and micrometers and they’re all in thousandths… can’t conceive of where you might have got a 1/128 one from…. and having got one, persist in blaming the world for your acquisition of something that is patently useless to you.

  9. I was on a trip to New Zealand, turned the TV onto a DIY channel and was immediately jealous.

    In screen was a handyman using a metric measuring tape. All his measurements were in a single unit — centimeters. When he needed something smaller than a whole number, he would use a decimal after the whole number.

    This contrasts to the tape measure in my tool box which has to deal with feet, inches and fractions. Seriously? Fractions!

    I’d much rather add 55.1cm+10cm than adding 1ft5 1/4in + 4 1/16in.

    Metric system … I’m jealous!

    1. I can reduce your jealousy at least a smidge. Halve a dimension, say 10 cm. You get 5. Now half it 3 more times. What do you get? 0.625? You find that convenient? Now take 5in and do that and you get 2 1/2 and then on to 5/16, both nicely marked on your tape (and easily determine doing very simple, whole-number math applied to numerators and denominators.) We cut things in half all the time and SI sucks at that. Conventional measure is frequently a base-2 system with the occasional 3 thrown in where useful because we like to divide things in thirds, too.

          1. But, what if I want to measure 1/3 inches or 1/3 ounces or pounds, or quarts or gallons? Three is only a factor in feet. Why isn’t it a factor in all units?

            In metric countries, the building module is increments of 100 mm and 200, 300, 600, 900, 1200, 1800, 2400, 4800, etc are normal sizes and can all be divided in thirds if needed. but how often is it needed?

            The metric system does not dictate sizes, the use does. So pick sizes that tat work with the divisions you want to use. Pick volumes and masses in 30 mL or 30 g increments and you can divide by 3 all day if that makes you happy.

          2. Sure. What if you want 1/3in? That isn’t frequently encountered, but it might happen. The point is that for frequently done things, there are factors available. For less frequently done things, the process might be a bit more complicated, but no more complicated than in SI.

          3. And your example is a fine argument against. Notice how, when they have a great base-10 system, they choose their standard sizes to have all kinds of factors for exactly the reasons I mention in favor of Conventional Measure which has those factors already built in.

      1. Take take 5 inches and halve it 4 times, and I get .3125 inches, which is what I need to use on my imperial milling machine. (Someone decided fractions might be a bad idea before they got down to 1024ths of an inch)

        While I do see the advantage of having a base with more factors, once you start getting into odd numbers of 64ths The math starts to get a little twisty to do in your head anyway, and you’ll be using the same decimals us metric people do except in inches instead of cm.

        Where imperial gets messy is when you have a large dynamic range. There are occasionally cases where you need to calculate from cm to km, and that’s a whole lot easier than inches to miles.

        1. So are you discarding your milling machine to buy a metric one? I suspect not, and that’s the situation in a number of areas where American Standard holds. As for inches-to-miles vs cm to km I suspect that the number of times either one of those situations comes up is so small that it rounds to zero.

          1. When someone wants metric work done, you don’t go to a shop that doesn’t have a metric milling machine. That would mean you don’t give your business to an American shop. I’m sure the auto industry stop using American machine shops decades ago or found enough that have metric machines and work only in metric.

          2. And yet they persist. Look it’s a market call and if there isn’t a demand for shops that work in thous, they will go on their own. For those legacy industries, as long as they are competitive without changing, why should they?

          3. Nonsense, horseshit, bee farts. “When someone wants metric work done, you don’t go to a shop that doesn’t have a metric milling machine.” I haven’t seen a machine shop in several decades who couldn’t do work specified in mm. Even on their inch-calibrated machines. It’s not rocket science. You divide by 25.4. Even for making metric threads on an inch machine, you use a 127/128 gear combination to make the conversion, and you’re good to go in metric. This was all worked out fifty years ago.

        2. True. It is a factor (no pun intended) of most frequent use. I’d never use fractional inches for machining, where I revert to decimal thousandths of an inch, just like SI so that is no actual advantage of SI. But for woodworking 1/64 is as good as one can hold tolerance, anyway and the simpler math of the fractions without a calculator rules. Same in the kitchen with cups, pints, quarts, tablespoons and teaspoons. All useful factors of two and three for scaling recipes for 2,3,4 people, etc.

        3. Considering the whole world is metric I would prefer to hear from among them this problem. How do they divide numbers in halves and thirds? If they do, is there a problem? Obviously not because no one is complaining.

          In the metric world I would never use 5 inches, I would use maybe 125 mm or 130 mm and divided four times I would get 31.25 mm or 32.5 mm which is perfectly measurable with any device, even a ruler with only a whole number of millimetres. But in the metric world clumsy numbers are avoided. It’s sad that you have these problems and think incorrectly we in the metric world have the same. The system is versatile and works for us, obviously this is not true and you struggle with inches.

          Your way is a mess because you have to work with decimals when your inches are normally divided into fractions. Some decimal inches don’t relate to fractions unless you use large denominators that most people can’t relate too. More factors just mean more of a muddle and costly errors. That is why we went metric in the world to get away from these problems.

          The inch is too big for machining work, requiring numbers with 4 or more decimal digits, where metric is mostly a whole number of millimetres and rarely are decimal parts encountered.

          1. [Daniel Jackson]: Oh jeez. Again? “The inch is too big for machining work”. Which is why every place I’ve ever worked, we used thousandths of an inch for anything less than an inch. And is it really a problem for you to use a decimal point? And then, is the millimeter small enough for everything you need to specify? This is not logical argument.

      2. ” We cut things in half all the time and SI sucks at that.”

        Here’s the thing about cutting things in half: you don’t get halves. That’s because your saw blade has a thickness, so your two parts will be unequal in size.

        Knowing that, what is the use of halving and halving when you know the error will just keep growing each time? If you take a piece of wood and cut it in half, and cut the halves in half, and the halves halves in half, you end up with a pile of scrap wood because none of them are equal in size.

        Meanwhile the metric guy comes along and goes “Hmm… I need 16 pieces of wood 115 mm in length” and sets his table saw fence for 115 mm, and cuts 16 pieces all equal in size.

        1. Really? It’s not cutting things in half, it is scaling by half. Arguments like that suggest to me that the person making them argues about this subject much more than they actually use measurement scales for meaningful work. A chef reducing a recipe that serves 4 to be suitable for serving 2 doesn’t make up the meal for 4 and them cut it in half, they scale the recipe in half. And then there is feature location. In rough carpentry, If you want 5 joists even spaced across 2 headers (for 4 equal sized spaces), you need to be able to divide a distance by 4, quickly, easily and in your head.

    2. I’m surprised you encountered centimetres. This unit is not used in engineering nor manufacturing. The millimetre is the universal unit. With it there is no need for decimal parts. Thus 551 mm to 100 mm is 651 mm. Most of us though would make our products to measure 550 mm and keep the numbers to whole tens as much as possible.

      1. So my yard is 25,908mm by 38,100mm? I don’t think so. Even in SI, different units are used for different applications, there is no “universal unit”. Precision engineering (not civil engineering, for instance) uses smaller units like mm (actually, 1/10 and 1/100 of a mm for which there are no discrete prefixes) or, in conventional measure, mils = 1/1000 inch. And whyfore does SI even have a decimeter or centimeter if there is no use for it? I think you’ll find that carpentry uses Meters and centimeters if they are using SI, just like they use feet and inches if they are using Conventional Measure. I’ve never actually seen a use for a decimeter, mostly I’ve just seen people use 1/10 of a meter.

  10. Ok, so there are shortcomings of both systems, but, this entire article sounds like it was written by soneone who has lost and hasn’t yet accepted it. Sure metric has some issues, that list of issues is far smaller than the imperial system.
    I don’t actually need to remember much to know that 1L of water weighs 1kg and has a volume of 1 cubic metre.

    1. More than you do, apparently. :-) 1L of water has the volume of 1/1000 of a cubic meter of water. Nevertheless, this is one of the few accessible conversions where SI has an advantage over conventional measure. The list is actually quite long. Within any industry, in commerce, conventional measure works quite well, often quite a bit better.

      1. I wouldn’t say “one of the few”. There’s plenty of examples in both systems, and they all work really nicely when one of the units you’re converting is based on the other unit. (Water is used for a lot of metric definitions)

          1. Actually, an Imperial pint of water is 1.25 lbm. An American pint is about 1.042 lbm. A 4.2% error is not so “accurate” by modern day standards. Close enough for Middle Age peasants, I suppose. There are probably a few other pints I know nothing about.

          2. The Imperial pint (of water) is 1.25 lbm. The US pint, about 1.04 lbm., so no, a pint isn’t a pound the world around. Before the Commonwealth countries went metric faster than the UK, the Imperial pint was actually the more common around the world.

      2. “Conventional units” don’t work quite well. The majority of the world uses metric only, and they are the majority. The remnant using USC is usually some old dank, dirty sweatshop struggling to keep the doors open with costly work due to the inefficiency and mistakes made when using obsolete units.

  11. The most common imperial/metric problems I face are with pushbikes (here in the UK).
    I get a new or 2nd hand bike and depending on the bikes’ era, is either full imperial or mixed bag imperial/metric.

    Either a peasant grade wheel spindle bolt (on the cheap-new) or a worn out one (2nd hand) finally snaps from fatigue (2nd hand) or plastic deformity (cheap bike)

    Almost all fixtures for the wheels are imperial, But the spares can only be found in metric and that is only good if all the fixtures are the same, reusing imperial threaded bolts unknowingly on wheels have given me a few “fun” accidents (I check if the fixing nut wobbles on the thread these days before trying another bodge).

    I think we (collectively as humanity) should all stick to one measurement or the other, I don’t care which one.

    1. Pffft, it’s down to only two now? There was at least 5, Metric, Standard Imperial, British Standard Whitworth, British Standard Cycle, and Raleigh’s own system…. and for all I know there was more pre-war.

      1. Forgot about Raleigh’ own standards. Haven’t heard of the others until now.

        Imp+Met seems the most common for the wheel spindle bolt thickness+threading.

        Bottom brackets, I’ve seen a few types, though I thought those types I don’t normally see were some physical form of DRM (as far as I was aware), a: when-it-breaks, bin-it(TM) kind of ordeal.

    1. Because a something the size of a gram is generally hard to manufacture with similar precision to something 1000 times greater. Likewise the other way. 1 tonne is a bit difficult to manipulate. 1kg is more or less a convenient size. More or less like a pound. Go figure.

      1. Nope. Not at all. The ‘gram’ was originally defined that way because they could do it precisely.

        We ended up with kilogram as the base unit, rather than gram as the base unit, so that it would match up to conventional *electrical* units (ohms, farads, volts, amps) – so that the unit of electrical work (a volt-amp-second) equaled the unit of mechanical work (force times distance). You needed a scaling off of centimeter-gram-second (which combine to give you the erg) that would equal the scaling from ergs to joules (10,000,0000). So you go up 2 powers of 10 in length, and 3 in mass.

        Ideally you would’ve just renamed the ‘kilogram’ unit to something new, to have the system be lexically consistent, but that wasn’t that big a deal.

        But no, the choice of meter, kilogram, second as the base units from which others are derived was absolutely not due to the convenient size of the kilogram.

    2. I’d also argue that the (metric, not SI) meter being 1/10,000,000 the distance from the north pole to the equator running through Paris isn’t exactly a convenient standard, either.

      1. It was never really used either. The real distance using modern data for ellipsoid earth is closer to 10002 km. But they immediately made a bar, it was a little off, but it became the standard, and each refinement since has matched the original bar while being more reproducible. Most of us are quite happy using secondary, tertiary, or even lower standards, like a meter stick or tape measure.

        1. In other words, they developed a standard, it was a little silly, but it became the standard, and so even though *now* its definition looks a little silly, it sticks around because it’s been the standard for so long.

          … which sounds exactly like the reason that US customary units stick around.

          1. Well, Customary units scale in a bizarre series of ratios, which, in fact differ for each type of unit, and the units are a mishmash that causes lots of problems in engineering computations. Other than that, exactly like the SI, which is a system instead of mishmash, and each type of unit scales the same way (powers of ten).

            Oh, and one unit (scaled with prefixes) for each type of quantity like power or energy, as opposed to British Thermal units, horsepower hours, foot pounds, and measuring power in horses seems a bit odd, somewhat peasant-like, given that most of us have no experience with work-animals, and racing horses and draft horses are quite different.

    1. The British system is Imperial, named for the Imperial Act of 1824. The US system is called Customary and is different. The units of volume (gallon, bushel, and all subdivisions) differ from Imperial. In addition, more Americans understand the kilogram than the stone, with the result that our hundredweight is a sensible 100 lbm and the ton, 2000 lbm.

      Standard or english may be used to refer to a mishmash of both. The SAE went metric with the auto industry decades ago and regrets its standardization of hexheads on bolts from the 1930’s. (In truth the SAE does have an aeronautical group and does still issue inch-based standards primary for aviation; but the various ground transportation groups within SAE are now metric.)

    2. It is really USC for United States Customary. USC is not a recognised system, but a collection of unrelated units. SAE is the Society of automotive Engineers and they went metric decades ago. Their USC specs have been mothballed and are never updated to meet new technology. They only presently support metric standards and practices.

  12. I think the debate should not be between metric and imperial but between particularism and universalism.

    For instance, even in metric countries, people have a tendency to use Watts for electrical power, Horsepower for engines, BTU or calories per hour for heating/refrigetation (with the added problem that you dont know if it is really cal or Kcal), how many homes you can power for photovoltaic plants, A, B, C, D, E for energy consumption (or savings) for appliances. Other examples are inches for computer or TV display as well as mountain bike tires, but not road bike tires, go figure.

    It is not that I want to attempt fitting a computer screen on my road bike, but I prefer a single universal system not requiring conversions for the same physical parameter.

  13. Measurement systems Pffft, if you can’t specify something using geometric construction using only a pencil, straight edge and compass then your calculations are not based in reality.

  14. Fahrenheit is 80% more precise than Centigrade without having to get into sub-degree numbers.

    Then there’s ways of writing dates. Go from smallest quantity to largest. 12 months, 365 or 366 days, infinity of years. January 1, 2017 makes more sense to me than 1 January 2017 with the smallest quantity in the middle.

      1. However, Fahrenheit originally defined it, it is now defined by metric standards like every other Imperial unit. It is 32 when the temperature is 0 °C, as is 212 when the temperature is 100 °C, and increase by 1.8 for each 1 °C increase in temperature. End of definition.

        Since the ITS-90 temperature scale, water doesn’t freeze at exactly 0 °C and 100 °c, it is a few millikelvins off,

      1. Yeah, you got the dates thing backward. ALL numerical quantities should be written with the most-significant part first (to the left). Therefore it should ALWAYS be year-month-day. In the U.S., the NIST has declared this to be the preferred format for dates. To avoid confusion, use four digits for the year.

        In addition to making sense anywhere in the world, if you date files on a computer this way, they will show up in the correct order. Day-month-year is pretty much the worst possible arrangement.

    1. Nonsense. Compare the two:



      Fahrenheit thermometers resolve to every two degrees. Celsius to every one degree. One degree Celsius is more precise that two degrees Fahrenheit. The Celsius thermometer goes from -50 to +50 with zero at the centre of which most temperatures in the world will fall, yet Fahrenheit goes from -60 to +120 with 32 in the middle. Fahrenheit is very poorly organised.

      The true way to write the date would be 2017-01-15 per ISO-8601

  15. Really amusing this discussion.
    I live in Austria and grew up with the metric system.
    Naturally the metric system is more convenient for me since it’s the one I am used to.
    Just recently I built a pottery wheel by imperial measures.
    There e.g. it calls for wooden legs 2x3x32″. I don’t own an imperial measuring tape.
    Doing the regular conversion by 1″ = 25,4mm I would end up cutting wood 50,8×76,2×812,8mm,
    very arquard I admit.
    So why I should’nt make my life simpler? Use 1″ = 25mm for conversion and you end up with
    a piece that measures 50x75x800mm, pretty nice figures now and close enough in size for a woodworking project. The error ratio is 25,4/25 =1,016 which amounts to an error of 1,16%
    Even for the required steel rod of 1x 36″ this error is tolerable. A steel rod of 25mm is just as durable as one of dia 1″, and even more convenient, I can buy it and the appropriate bearing in Austria, no need to order imperial stuff from overseas!
    So what’s the fuzz all about this?

  16. For people who think it is about round numbers, a foot is ~ the distance travelled by light in 1/1,000,000,000 second, MUCH nicer than 1/299,792,458. This debate has, for me, become pretty silly and almost completely informed by biases, misinformation and eurocentrism. Conventional measure is full of domain specific unit sets all based on EXACTLY the same standards as SI but with sizes that are convenient for the domain they are used in and a pain in the ass to convert to use in other domains. SI tries to provide a one size fits all set of units and is therefore convenient for few systems outside of computing, science and engineering. In other words, often lousy for commerce.

    1. I point out that India and china both are “Metric” countries. That outweighs the US and EU combined preference by a factor greater than 3.

      Oddly, commerce is one of the major arguments for a unified measurement system, and most US goods intended for international commerce are marked in metric for exactly that reason . . .

        1. Americans may think of shipping containers in feet and barrels but In the world they are thought of in metres and tonnes. Yes, tonnes, we buy by mass and not volume, this way we get the amount we contracted for winter or summer. Volume changes with temperature.

        1. Wrong. The speed of light is exactly 299792458 m/s and with a foot equal to exactly 0.3048 m, the speed of light in feet is 91 376 741.1948 never ending feet per second or 0.91 376 741 194 8 never ending feet per nanosecond. Your assumption is in error of about 9.5 %. Which is OK since the foot is basically error prone to begin with.

    2. Oddly, 95% of the world finds it acceptable for commerce, so I suspect we would too. But I’m an American, conservative Republican, STEM professional who likes it because it works better in math, science and engineering, and I wonder why I need to use this other crap in my home life. Being forced to know two systems is a waste of my time.

  17. You might take notice and recognize that we’re outnumbered. If the world were to vote, it would be roughly 384 million for imperial (or US customary) and roughly 7,016 million for metric (or SI).

    Also, if you can’t handle metric at the SCIENCE Olympiad, you might spend your better time elsewhere.

  18. It’s fine if people want to measure with whatever body part thaey want. Because when you estimate you miss calculate by so much that isn’t usefull to any engeneering or architechtual application.
    People take 3 feet as a yard in the same way a long step is a meter, and they both miss.
    Imperial system is only used by three countries in the world, is just a matter of time to be replaced by the metric system as an official measurement system.
    But people will still use the imperial for everyday guessing.
    In the same way that old folks in my country ask for “2 inches tubes” and they get a 50mm tube. Off course they aren’t high precision machinist or anything.
    One good thing is that now in my country the 3/4″ round bar was replaced by the 20mm bar, slightly bigger. Allow me to buy that isntead of a 7/8″ bar and have to reduce the diameter to 20mm.

  19. Talk about missing the point. This is silly. Those are not the relevant problems. The imperial system is inconsistent, arcane, and isolated.
    Inconsistent because there is no common way to deal with different scales across different quantities: length has power of two fractions of inches, then 12 inches in a foot, and god knows how many feet in a yard or a mile. Then you have ounces, gallons, and other unrelated units of volumes. I could go on. With metric, you have powers of ten (convenient when you compute in base ten like we do) that apply to all units: km, kg, etc. The only bump is time, but that’s not specific to metric.
    Arcane because there is more than one unit for a given quantity, and for combinations of quantities. Metric can be almost entirely summarized with meters, Kelvins, seconds, and Amperes, and their combinations.
    Isolated because only two countries in the world did not get the memo. Standards can be good.
    Let’s add that there’s not one thing that imperial does better. This is all cultural stubbornness and… imperialism?

    1. Another unit doesnt bother me, multiple unit definitions for the same thing are arcane indeed :). Only mistake in your story is: km and kg arent units, gram is a unit and meter is a unit, k is a multiplier. Why cant imperial do kilo yards or milli yards etc?

          1. I agree. I wasn’t arguing that. I was arguing with the assertion that you can’t measure very small things in inches.

            People keep trying to change this from a units of measure discussion to one of numerical notation. The two things are completely independent.

          2. Right, the scaling argument is BS, could set 0 to absolute zero and highest temp of plasma theoretically possible to 1, call it the Banana scale and we’d all get along with the weather forecasters telling us it was 30 milliBananas today and all know what he was talking about.

  20. I just want to point out that all of you leaning on the powers of ten argument are showing everyone that actually works with measurements for a living that you do not. That is the very least of the reasons we should have one system.

  21. As some people here have pointed out: metric is the more powerful system, because it makes relating different units and relating the same units at different scales easy.

    It’s easy to convert between units of energy or force to distance to volume to mass, because they’re all designed to work together. This means that you can spend more time thinking about the consequences of how real things in the real world relate, rather than trying to work out how many foot-pound acres per square fortnight you need if the original unit was gallons.

    And once you can relate to things in the real world, you have greater power. Hence metric is literally a more powerful system.

  22. Most of the examples cited are just contrived. It doesn’t matter. Many units are related to human body dimensions and capabilities (eg. so many miles march in a day, English or Roman). In the UK we use dual systems, road distances are in miles as are car speedometers. But petrol is in litres and yet drivers ask about the mpg a car gets. In any case the Imperial systems was *given* to the US by the UK. And I find I don’t have to consciously *convert* between Imperial and Metric I just *know* both values in most cases that I need to. But please could the US stop refering to thou as mils. Thank you.

  23. My issue is when I have to perform math functions with the imperial system. 13 3/16″ needs to be divided into 7 equal parts…. 1.88392 inches… I create scale models a few times a year. Converting decimal inches to factions so I can measure them on my tape measure. Over and over again. It just seems dumb. I am going to get a metric tape measure.

  24. I daily deal with imperial to metric conversion given oilfield tools which are predominantly given in imperial sizes and communicating to manufacturers/suppliers in metric. Each system has its place and uses however metric is more widely accepted outside USA markets.

  25. Well, this is the dictionary definition of a troll article then eh. And not being that subtle.

    I get that it gets lots of comment and attention and that draws in visitors, but please don’t overdo all the troll articles. And please troll with a bit of real content and do a little effort.

  26. Learning the Imperial system at an early age, if only the most commonly used units (ignore the long ton, Troy and Avoirdupois ounces…), teaches the brain flexibility. Ten isn’t the only base out there, and it isn’t the best. If God or Nature had provided us with twelve or sixteen appendages and we’s started counting on them, we’d have a number system with twelve or sixteen different digits. A friend with a PhD once argued “…but the decimal system is EASY!” It’s only easy because we have a numbering system with ten digits. She wasn’t even aware that that’s a self-imposed restriction, a throwback to counting on fingers. Anyone who can do hexadecimal calculations in their head will know what I mean.

    Let’s not tie ourselves down to one base, and a poor one at that.

  27. I had expected some of those feverishly defending imperial systems (look whatever works right, but then only if it works..) point out a real irregularity (but not inconsistency) with SI units, but since no one has, here it is:

    disregarding prefixes, units convert easily: i.e. 1 N / m^2 = 1 Pa … 1 Ohm * 1 A = 1 V … and so on
    but then you have 1 kg * m / s^2 = 1 N but that had a prefix, and without prefixes its 1000 g * m / s^2 = 1 N
    now people who are used to SI, know to use kg for combining units, but then really use prefixes with respect to g… (i.e. a kkg does not exist, and we use mg for milligram and not a microkg…)

    1. so I kind of understand people defending the imperial system, although I dislike it, it is a matter of habit…
      I could easily imagine some “new SI” system replacing the kg with the Oomph, so 1 kg is 1 Oomph, and we have 1 Oomph * m / s^2 = 1 N, nice and regular, and then a gram would be one mOomph… a milligram a microOomph etc…

      the whole idea disgusts me, so I can sympathize with those defending imperial units, just like I can sympathize with smokers not quitting…

        1. would you denote a 1000 kg as “kmillitonnes” or as a tonne again? if the first its awkward, if the second:
          1 millitonne * m / s^2 = 1 N so 1 tonne * m / s^2 = 1000 N so the units for different dimensions no longer convert without generating conversion coefficients…

      1. Happens all the time. I’m sure you’re not happy with the popular choice to replace AD and BC in dates with CE and BCE. This came as a surprise to me – nobody said anything or reached any kind of consensus; they just started using the new names.

  28. I was always under the impression that the imperial system is a somewhat obscure way to address the needs of people who only know basic maths. As in, basic operations above 20 are hard, more than 100 is nearly impossible, and exponential notation is unheard of.

    1. Contrariwise!!! If the imperial system was left in place so morons could still measure things, then the metric system wouldn’t have all of those prefixes. Scientists and engineers don’t need the prefixes, and in fact the prefixes just confuse things, because they already have a viable system for large and small numbers – exponential notation. Although now that I think about it, most engineers seem to prefer using the prefixes. Nevermind.

    2. Yes, that is true. Imperial and USC were “designed” to take advantage of the illiterate and innumerate in the bygone days by creating a means by which marketers could cheat customers. We have or should be moving past this point for a need to deceive consumers.

  29. Well, basically the most interesting thing is resolution. As a Machinist my base measurement is a mm, which i can divide into 1/1000 of a mm. need i say more? btw id do lik the fraction stuff [and need to use frequently] but when precision is goal mm’s rule, sorry folks

    oh and since we are all brothers [and sisters] working together worldwide, one measuring system would be jolly great wouldn’t it?

        1. [Daniel Jackson]: Again, you’re commenting out of context. MY comment was in opposition to the assertion that U.S. customary units are useless for small measurements, which was based on the ignorant belief that “inches” means “binary fractions of an inch”, which is a stupid straw man argument made in a discussion where metric wins by a (sorry) country mile WITHOUT having to resort to bad logic. I WOULD PREFER U.S. CUSTOMARY UNITS TO BE BANNED. But I don’t listen to nonsense gladly.

  30. Customary units make calculations easier. Like if you have a weight you want to divide by 21 you just take the value in stones and multiply by 2/3 of a pound. In metric it would be 47.619 grams per kilogram, which is ridiculous.

  31. Both systems have their purposes. I can pace out my field with my feet, and be accurate within a couple of feet over hundreds. I can measure a pretty accurate inch with my finger. I can drink a pint or two if I am thirsty. The thing is most imperial units are based on some aspect of out physicality, and I don’t see that as a bad thing. Make fun of it because tere are so many weird units, but they have their roots, and they have (or had) their place.

    The weird thing is that metric units are based on things that are just as obscure, and have changed over times. Take a look at the definition of a meter for example. We are on the third or fourth incarnation of it’s definition, and trust me, none of them are based on anything in which you can relate to physically on a personal basis.

    What most people incorrectly refer to the nice thing abut the metric system are the neat prefixes, and I will agree, they are neat and handy, but, they have nothing to do with the base units.

    And in various engineering disciplines you occasionally see happy mixes of imperial units and the power of ten prefixes. Explosive charges were expressed in their equivalent of tons of TNT. Than they got bigger so they started expressing them in kilo tons, and with the H bomb, we entered megatons. I have heard of money expressed in kilobucks. Thousands of an inch have been expressed as mils for a long time.

    So, if you like the prefixes, that’s cool, use them, but don’t go praising the metric system based on the prefixes when the base units are as obscure as any imperial unit, and far removed from anything you can get a rough double check with only using your body.

  32. I do not give a flying fucked rats ass what unit of measurement is used as long as there is consistency throughout it’s usage and allowance for conversion to other units- also, I’m currently drunk, so I deserve any crucifixion for this comment.

    1. The main problem is that SI and USC don’t relate to each other nicely. If you got rid of fractional inches, went to a 25 mm inch and a 30 g or 30 ml ounce, then the numbers in for the same measurement would be round in both and it wouldn’t matter.

      If a 50 inch TV screen was also 1500 mm, it wouldn’t matter. If a soft drink was 11 ounces or 330 mL, it wouldn’t matter. Both would be round numbers and everyone would be happy.

      1. Some times the numbers ARE fairly close. Even when I worked in the semiconductor industry, where everything is measured exclusively in mm, it was pretty common to call a 150 mm wafer fab “the 6 inch line”. And our whole lumber industry has been infiltrated with 13 mm plywood that we just call “half-inch”, and rolls of 50 mm adhesive tape we call “two inch”.

        People seem to like defending the inch to the very end, not even realizing that it’s almost gone already.

        And then there are those OTHER times, like the “size” of image sensors (not talking TVs here), and plumbing pipe, where the inch measurements aren’t even close to any physical dimension on the product. But for rules-of-thumb, there are some easy ones, like a meter is close to 40″, so a 50″ TV is about 1.2 m. See? Some of us “muricans” can do arithmetic.

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