In defence of imperial units

Published August 28th, 2007 edit replace rm!

The imperial units such as pounds, inches and feet have been receiving a fair about of criticisms and ridicule in the blogosphere recently (of course I can’t find the posts I’ve stumbled upon recently). Around learned people and in international crowds this is bound to happen fairly often. Of course the battle has been going on for centuries.

As someone who grew up in Denmark with the metric system yet also grew up making pancakes from recipes in the Joy of Cooking I am fairly used to both systems and would like to take a bit of a contrarian defense of Imperial Units..

Let me first state that I like both systems of units and both have their uses. Also contrary to the argumentation of many European’s you are not stupid if you don’t understand metric, nor the other way around.

So the big advantage of the metric system is that it is easy to convert say from centimeters to meters to kilometers by cutting or adding 0’s off the end of a number. There in lies it’s genius.

Many people also add that the metric system is based on real verifiable physical properties such as the distance travelled by light in an absolute vacuum during 1/299,792,458 of a second. I would like to say that this is about as useless and arbitrary in daily life that seriously, who cares? Scientists and engineers do of course, but in daily use no one else.

So I’d say conversion and international standards are the most important aspects of metric units. However the fact that all units are based of decimal multiples of each other in some form or the other, is also the cause of the largest usability problem with it.

The metric system was originally developed by scientists during the enlightenment, but became the political tool it is today as part of the French revolution, yes it was brought to you by the good folks who also brought you the guillotine. Thus it was imposed on people from above to better their lives. This is also what has happened every other country in the world except it appears the US, Liberia and Myanmar (metrics that is, not the guillotine):

While standardized differently various parts of the world the Imperial Units essentially evolved organically over thousands of years by people. While prior to standardization not very precise measures were possible, they were all based on real world reference points that gave you an idea of their uses.

Thus a foot is well the length of a human foot. Miles come from the latin word for thousand and basically means 1000 paces and goes back to the roman days. A cup, is well a cup. An inch is a thumb length.

Most of the old units are gone now, but the most useful ones are still with us. Why? Well because they reflect useful sizes in daily use. So if you take a moment and look at it from a usability dimension like most of us web application designers like to think we can do.

A cup or a foot or a pound might just be more usable during actual daily use. Lets think about it. For measuring the length of something smallish like a notebook 15 inches just seems easier to relate to than 38 cm. I’m sure a psychologist could explain it better.

When measuring a room feet just seems an easier unit to eyeball. I could eyeball meters but not as exactly as with feet. The keyword here is eyeballing. Anything that can be eyeballed more or less might be easier to use with imperial units.

Cups and pounds relate much better to real portion sizes in a traditional home kitchen. Almost all recipe’s call for a pound of meat as it’s a kind of natural portion amount of meat to cook with. The same with cups of liquid. It’s way more natural to use a cup of liquid as the base of a recipe than deciliters.

That is the beauty of the imperial system is that because they were evolved and not specified they are naturally easier for us to relate to. In other words for the uses they were originally designed they are more usable.

However the needs of engineers, scientists and 7th grade maths students are very different. It is obviously a lot easier when you are trying to understand or change the world to have a common frame of reference and easy conversions. For them the metric system is great.

Everyone says the US is not metric. What that means is that the US hasn’t invented a law yet to say that we’re metric. This is all it means. For all intents and purposes the Americans who need to be metric are metric. Scientist, engineers, big business and designers already metric.Why? Because it makes sense for them in their trades. Almost all grocery’s also have metric units listed on the packaging.

Why do ordinary people have to be forced into using metrics in their kitchen or measuring their living room prior to going to Ikea? The answer is they don’t. The metrification map
I linked to above shows pretty much a metric world. But what it doesn’t tell you is what people still use in daily use.

England is listed as being metric. That is a joke. Everyone in England thinks in pounds, stones (yes stones), miles and feet. Panama is listed as being metric since the 20s. But if you go to the meat counter in the super market and order “medio kilo de carne molida” you will receive blank stares (and possibly a “gringo loco” under the breath). They use pounds, inches etc just like the US.

Obviously there are lots of countries that are metric, such as Denmark, Germany and Franche. But even highly metric Denmark still has remnants of it’s evolved units that stubbornly refuses to die purely for reasons of usability. Recipe’s don’t talk about using 15 milliliter’s worth of sugar but 1 tablespoon.

I’m sure every country has still got their own traditionally evolved units in use in the markets, kitchen or even hidden in standardized portion size.

What about web developers. It’s generally recommended that we use a combination of evolved units such as em’s and points as it is designed to be usable and adaptive for humans. Pixel’s while more natural to us engineers are not quite as useful for our endusers with different screens, computers and vision.

By their very nature I am also guessing that evolved units such as feet and cups grew as people grew and became healthier over the centuries. And why not? As appetites grew the cup size grew, but the recipes stayed the same. It makes a lot of sense to measure your living space based on your actual foot size than some standardized version of a foot, as you are the one who is going to be living there.

So please, all I’m asking is less of the ridiculous flame war thats been going on the last century between metric and imperial. Both are good for their particular purposes.

Yes a generation trained to think metrically won’t normally have that much a problem dealing with it, but training is not the be all and end all of this. I’ve spent years programming in the rigid standardized world of Java, but I now prefer the far more flexible Ruby language as it’s more usable to me. I can relate to it better. Unit’s should be all about choosing the best tool for you for the task at hand.


Will Kamishlian August 28th, 2007

Wow, cool blog entry. I was just splaining this to a friend the other day. Units of measure are always arbitrary to some degree. You hit upon the idea of “eyeballing” a measurement. Note that metric units seem to have Imperial counterparts. It’s no coincidence that a meter is roughly equal to a yard, nor that a liter is roughly equal to a quart. Kilograms are close enough to pounds to be usable as the same type of measure, especially when you consider that it would have been just as scientific to measure a kilogram as the weight of a cubic meter of water.

Napoleon could have just as easily divided a yard into 1,000 units. That would not have eliminated metric to Imperial conversion; however, it would have made it more convenient. The same is true for quarts, kilograms, etc.

When someone casts aspersion on the Imperial system, we might ask why he or she does not recognize the decimal calendar system. Napoleon attempted that, too, and it makes more “scientific” sense than our current system of seven day weeks and months with days varying from 28 to 31.

Pelle August 28th, 2007

Great point about the calendar and time system. I hadn’t thought about that.

Andrew Vit August 28th, 2007

As a Canadian I’m a fan of both systems by necessity, and use either where it’s appropriate. Celsius makes more sense than Fahrenheit (except for setting the oven), but feet and inches make more sense for construction.

One usability point that the imperial system wins over metric is the divisibility of its units. Being twelve inches, a foot can be evenly divided by 2, 3, 4, or 6. Same goes for those units that are made up of sixteens (pounds/ounces): this lets you cut the unit in half 4 times over before having to deal with a decimal point.

If only we were born with 12 or 16 fingers, we’d have a natural counting system (base-12 or -16) that matches up better with the more practical divisibility of Imperial units.

Still, if the world has come to a consensus and decided on metric (whether we’re all 100% metric or not), it shouldn’t be a matter of ideology for the US to be the odd man out…

Andy August 30th, 2007

My cup is “engineered” with the metric system in mind and holds 200cl (afaik). Well depends on the cup I use today. ;-)

Everything around me is designed, build and made with the metric system in mind. I have alot of reference around me in my daily life.

Acutally, it is harder for me to understand what 15" are if I didn’t had that old CRT monitor. I have a better feeling for 38cm.

If people from the US are talking about their height, I really don’t know what they are talking about. If someone says 6feet, then it doesn’t sounds familiar to me, and I can’t make myself a picture about the person. If you tell me the person is 183cm or 1.83m then I can imagine it.

My country made the transition to the metric system, and it took a while to get used to it for all the people. But it isn’t that hard, and a country like the USA should also be able to do it. All the talking about the costs and whatever they are talking about to not introduce the metric system in a whole scale in the USA is something that I really can’t understand.

Loïc d'Anterroches September 3rd, 2007

Being French, I can tell you that we are still using table/coffee spoon metrics when cooking. The problem with imperial units is not really the conversion, the problem is that very often you end up with a distance in “miles/once/whatever” but you have no idea which one the people are using. Is it an English/Nautical or US one?

On the other side, it makes travelling way more interesting :)

Lau September 5th, 2007

I think you should use a unit that is appropriate for the situation. A table spoon or tea spoon is appropriate for cooking. Nautical miles are appropriate for sailing. Yards are appropriate for American football. But I don’t see things like fluid ounces or pounds per square inch or Fahrenheit or gallons being appropriate for a lot of situations.

I don’t think it matters too much what the units are based. Ie. a foot or the size of the earth. Sometimes it’s useful though – for instance Celsius having 0 and 100 degrees related to the phases of water.

But in metric you can convert between “big” or “small” measures easily. And length and weight have can be converted when you work with water, which is essential to humans.

For instance: If you tell me that you have a fish tank that measures 2×2×1 meters on the inside, I can tell you have much water it can hold (4 cubic meters or or 4000liters) and how much the water weighs (in 4000kg or 4tons or 4,000,000gram or whatever). This is easier on my human brain than if I used imperial measures.

If I told you about a fish tank that is 2yardsx2feetx10inches and you filled it up with water, how much would the water weigh in pounds or stones? How many fluid ounces would it be?

Heather February 12th, 2009

Really? “Imperial is just more natural” because that’s what you’re used to. My best friend grew up in Poland. When she moved to the US, she found it very difficult & ‘unnatural’ to make measurements in the Imperial system as she was used to the metric system. For her, metric made (and still makes) more sense.
Take this example from making a recent meal and tell me which is ‘easier’:
The food I was making called for 1 ¾ cups water and 1 ¼ cup of dry mix and 1 tablespoon butter. The end would net 3 cups. I didn’t want to have that much food, so I needed to reduce this recipe. Good thing I remember reducing fractions and solving for an unknown!
How I solved it:
Common factor = ¼
1 ¾ has 7 X ¼
1 ¼ has 5 X ¼
If I wanted to reduce the recipe to 1/3 of the original amounts, then here’s what I had to do;
Solve for the unknown: n/5 = 3/7…n = 3*5/7….n = 15/7…n = 2.1.
What the heck is 1/10 of a cup?! No more conversions!!! I added ¾ cup water and a little over ½ cup mix, and a small scoop of butter. It turned out ok. But the time I took and potential for error could have also cost me money if I screwed it up and had something inedible.

Now, if this were metric:
1.75 cups = 0.41L, 1.25 cups = 0.30L. If I wanted to reduce to 1/3, then I’d divide 0.41 and 0.30 both by 3. This results in 0.14L water and 0.10L of mix.

How about trying to figure a recipe when your ingredients come in pints, milliliters, ounces (dry & liquid), cups. Forget it! I’ll order carry-out!

We may still be able to cook with whatever units we choose, but in industry & trade the US will need to go metric if we want to remain competitive in the global marketplace.
From the US Metric Association (USMA), “The European Union (EU) directive on the approximation of the laws of the Member States relating to units of measurement is, in essence, the European law regarding measurement. It’s relevant to American companies because it will ban the use of dual units beginning in 2010.
In 1979, the EU, then known as the European Economic Community, approved Council Directive 80/181/EEC, which specified the International System of Units as the legal units of measurement in Europe (with appropriate exceptions) and, more significantly, forbade the use of “supplementary indications”—dual units—after 31 December 1999.
As it became clear that the deadline was a bit optimistic, Directive 1999/103/EC in January 2000 postponed the ban on supplementary indications for a decade, until 31 December 2009. So, beginning in 2010, it will generally be illegal to use dual units in the EU. And although this is usually described as a labeling law, it goes much farther than that. With a few exceptions, it applies to all measurements, not just package labels. It also covers measurements marked on items and measurements in product brochures, manuals, advertisements, etc. It would probably even require separate, metric-only Web sites for European visitors. Because the U.S. generally requires dual units and forbids metric-only labels, and Europe will require metric-only labels and forbid dual units, companies on both sides of the Atlantic will face challenges beginning in 2010.”

Pelle Braendgaard February 12th, 2009

Remember I grew up in Denmark immersed in the metric system.

For calculations the metric system is definitely hands down easiest.

But I do think things the base imperial measurements are easier to eye as they have a base in real world objects such as cup, foot, inch (based on the thumb) and pound.

This was my whole point is that the imperial system gets vilified by us Europeans in particular, but given it’s history it has it’s advantages in it’s usability. Half recipes are a pain though and for that Metric is way easier.

I always thought the EU laws which has caused quite an imperial rebellion in the UK are silly. As long as metric is specified, why is it so important to ban imperial. It stinks to me of forced reeducation as made famous by Lenin.

grim March 9th, 2009

Metric people are backwards too. Take for example the weight of an object. A common question. How much does it weigh? Cuánto él pesa? Weight and the spanish word ‘pesa’. Both signify the force an object has caused by the acceleration between two masses. Notice that even in metric converted society, they mention a KILO as being a unit of force. A Kilogram 1000 times the unit of a gram, which is a quantity of mass. Not a force. In recap a kilogram is a kilogram even if you enter a travel to the moon**. My weight decreases when I travel to the moon.

A second is NOT a unit in the metric system. Any derived units using a second such as velocity, acceleration, jerks, are also not a metric unit. Both imperial and metric share the second, its not based in either domain. Although one might define a meter as such for convienance.
  • I said that my mass will always remain constant, which is more or less true. But in reality as one approaches the speed of light, the energy required for such a speed actually has measurable mass. Also one of the reasons why a second is not a unit, is that that actual experiance of a second is not constant between two objects. Twins paradox, imagine two infinatly precise atomic-clocks. Fly one in a jet around the earth, and keep the other still, return them back to be next to each other. They will tell different time. (in our case the jet isn’t fast enough to really make a difference, but space ships travel faster). Also a photon of light or such electromagnetic particles that travel at the speed of light, experience no time in an infinite amount of our time. Take for example high energy particles that the sun emits. We know these particles self destruct within milliseconds of creation, but yet some travel the 10 or so minutes to earth and destruct when they are slowed down by the earths atmonsphere.

I hate doing calculations with English units, but seriously, metric is not the panacea. It has its own problems. One is precision. In English we pick the unit to signify the precision. Measure it in miles, it will be accurate to be within 1/10 of a mile. Measure it in inches, it will be accurate within 1/10 of an inch. Measure something in meters write it in kilometers. Information is lost. What about cooking. Why specify a meaningless decimal number of grams when I just want a teaspoon.

Jared March 9th, 2009

Let me know if you need a proofreader next time. It’s especially bad in critical pieces to have silly errors like this:
“There in lies it’s genius.”
should’ve been…
“Therein lies its genius.”

It’s still a bit smarmy, but now at least correct.

Josh February 18th, 2010

I don’t really like the metric system too much (i bet you know what nationality I am) but I do like the fact you can easily convert stuff, that’s nice. I also like using mm and cm to measure small items. Other than that I’m not a big fan of the rest. Compared to the imperial/American systems, numbers in the metric system seem to get really large. I don’t see how 175cm is easier to visualize then 5’9", or how 355ml is easier than 12 fluid ounces. And with the elimination of fractions, road signs say 500m, 750m and 1500m instead of 1/2km, 3/4km, and 1 1/2km. Also Celsius is not a great scale to measure temp in. The Fahrenheit scale was made specifically for measuring body temp, weather temp, etc. Celsius was made for the sake of having freezing 0 and boiling 100. Now you have to take the Fahrenheit scale and squish it down to fit the 0 and 100 range, creating the need for decimals (if you want to be as precise as Fahrenheit) and use negatives more often.

Michael October 29th, 2010

Metric units are inhuman in non-intuitive, but make the paperwork easier because they eliminate the fractions. So if you are a designer who cares about how objects will be used by humans, you want to think in human units. If you are a bureaucrat that only cares about paperwork, use metric.

I am an engineer that grew up in Australia with metric, but now work in the US. In my experience, its much easier to make an error of judgement when using metric. Imperial addresses the garbage-in-garbage-out problem much more effectively.

lol July 25th, 2011

imperial is for retards… that’s all

Jeff September 26th, 2011

‘Imperial is for retards – that’s all’?!? What a sad little comment.

The Imperial metric system is for usable measures (eg why do the decimal countries keep the pfund and the create the tonne?); the French decimal metric system is for playing games with decimal points. Which is more valuable?

Bernard November 13th, 2011

Now mush!

Jon February 15th, 2012

I have always worked with the metric system. Even at primary school (1979-1984) we did everything in the metric system, then later in science it was all metric.

However, many of my friends and family still use the imperial system. I really do not understand why, it is so much harder to measure anything.

I do have to work with both now, simply because so many clients are American and only use the imperial system. On the rare occasion that someone does use metric they always start by apologising!

a February 22nd, 2012

Thats just ridiculous.
“For measuring the length of something smallish like a notebook 15 inches just seems easier to relate to than 38 cm.”
What? o.O
I have absolutely no clue how much 15 inches might be, 38 cm i can see in my mind.

“Almost all recipe’s call for a pound of meat as it’s a kind of natural portion amount of meat to cook with.”

Almost all recipe’s call for a 0.5 kilogram.

me June 25th, 2012

I agree about the use of Imperial units during day-to-day activities, but how about keeping them out of engineering, mathematics and science? My biggest problem is that in the countries you mentioned the Imperial system is still used in those domains, leading to a harder way to communicate.

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