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Episode 2013: the imperial system strikes back

Small boy with a measuring tape and pencil

The imperial measurement system is not just still alive – it may be staging a comeback, according to reports. Should school children be taught to use both imperial and metric measurements?

Michael Gove, the Education Secretary, is apparently making plans to reintroduce the teaching of imperial units in schools. The draft curriculum for England is set to teach pupils how to convert between imperial and metric

I can see some logic for doing this in maths classes; the interview for my first job in a DIY chain had questions on converting feet into centimetres. My customers were a real mix of imperial and metric users, but I don’t recall imperial being taught at school. My knowledge was probably more down to my ruler using both measurements – it was a 12″ one with a rather odd 31cm on the other side.

So, should we just ditch imperial and spend time teaching kids about something else? JD Baines told us on our last imperial vs metric debate:

‘Few teachers now understand imperial, whereas in schools in the 40s, 50s, 60s and 70s decimal was taught in schools alongside imperial. One was taught the conversion factors as well, which were “simplified” on the official decimalisation on the UK – thus one could not go to a timber yard and get 50mm x 100mm – it was still 2″×4″. (50mm x 100mm is actually smaller!).’

Wavechange offered an alternative solution:

‘I am happy for kids to learn about imperial measures – but it should be in history classes.’

Your thoughts on the imperial march

When we last had a conversation about measurement systems, almost half of the voters in our poll thought we should ditch imperial units altogether, while a third thought we should keep our current mix. Over a fifth preferred a return to imperial. Some of the comments showed hard lines on the debate. Seares was ready to go metric; ‘It’s about bloody time.’

While David Ramsay spoke for imperial users:

‘NOOOOOOOOOO. I will refuse to use anything other than imperial and will ask for all purchases to be measured accordingly.’

John Knox was equally emphatic:

‘Imperial all the way! I still do everything pretty much in imperial. You know that the jars of jam and honey, etc. you buy are a pound in weight in the supermarket despite them putting the diabolical French measurements on instead.

‘A pint of milk is still a pint of milk and same for beer! We also know our quarter-pounder and half-pounder burgers!’

Popular abroad, the metric system is

The UK is not the only place to have converted from imperial to metric. Michael Glass offered a viewpoint from a country far, far away:

‘As an Australian I find all this angst about metrication quite appalling. Australia, New Zealand, South Africa and a whole lot of other countries changed without all this fuss and bother.’

Seares thinks we should go Dutch:

‘I’m in Holland – there doesn’t seem to be any problem here with metric, and they still have their own culture (and cheese). Why would we alone in our island lose our ‘nationality’ or ‘history’ or whatever if we used the system most other countries do?’

Finally, Swanseasteve pointed out that Sandringham listed its size in hectares:

‘If metric values are good enough for the Queen they’re good enough for us!’

What are your thoughts? Is the proposed move to teach imperial putting the best foot forward or taking us back by miles?

Should imperial measurements be taught in schools?

No, it's time to go fully metric (51%, 287 Votes)

Yes, they are helpful for daily life (38%, 215 Votes)

Only if they are taught in history lessons (11%, 60 Votes)

Total Voters: 566

Loading ... Loading ...

The arduous requirements for primary school teaching.
” A new primary school curriculum – published in draft form last year – says pupils should “understand and use basic equivalencies between metric and common imperial units and express them in approximate terms”.

Pupils are also told to convert “measurements of length, mass, volume and time from a smaller unit of measure to a larger unit, and vice-versa, including between miles and kilometres”. The current curriculum makes no mention of miles.

It adds that children should be introduced to “compound units for speed such as miles per hour and apply their knowledge in science”.

But a DfE spokesman said: “No significant change is planned. Imperial units are in the current curriculum and will be in the new curriculum. Both the mathematics and science curriculum, however, will continue to teach metric measures as standard.”

A lot of fuss about nothing. There is no need to rush these things as it will be dying out naturally over the next few decades. As international/exporting companies build in metric anyway what is the problem in ordering a pint for consumption in your local.

Nothing will ever die out for as long as we have miles on the roads and pints in the pub, and it is illegal to do otherwise.

Alex B says:
15 January 2013

See now this is precisely the problem… metric on road signs, for draught beer and doorstep deliveries of milk in glass bottles is actually illegal in the UK, the only place in the world where that is the case. Until that changes there will be little or no progress.

While parents are actively encouraged and/or forced to use imperial measures their children will not adopt them regardless of their education, they will continue to be confused and bemused as many of us who have had exclusively metric education already are.

The measurements we learnt as children, will always be our native system of measurement. It will be always be the easiest to understand, and use. All other measurements require conversion back to our native system of measurement, therefore making any other forieign measurements more difficult to understand and use. This works both ways, the metric only person will find Imperial difficult, and the Imperial only person will find metric difficult, but both will find their native systems of measurement, easy to memorise, and easy to imagine.
However the problem is that our children, our next generation, are not learning metric exclusively or Imperial exclusively but a mixture of both. This is a catalyst that adds to the mixed measure mess, that we dont need, and should be trying to eliminate. I am sure, that mixed measures, puts our children, and also later when they are adults, at a disadvantage to other people, from countries that learn only one system of measurement (metric). Its human to take the easiest path, and children will find that metric is easier to learn than Inperial, so metric will still be the primary system of measurement. I dont see the point in children learning about pints which are just containers for beer or milk, now that the gallon has disappeared. No doubt parents will still teach their children how to measure their height and weight in Imperial units. Its always these measurements, that are the last to metricate, when all other measurements around us have changed to metric.
The real solution to these problems is to restart, and complete the metrication process started 47 years ago, and set us on the path to a one measurement nation (metric), like so many other countries around the world. It will take a government with decisive goals, and political will, to “bite the bullet” and complete the metrication process. Unfortunally I dont see this happening anytime soon.

Sorry wjg “The measurements we learnt as children, will always be our native system of measurement. It will be always be the easiest to understand, and use. All other measurements require conversion back to our native system of measurement, therefore making any other forieign measurements more difficult to understand and use.”

That may be true in most cases, but such is my hatred of the Imperial “(non)system” and the horrendous calculations that comes with it, that I could never regard it as my native system. True it is very regrettably still all around me and I still (probably) think in feet for short measures (first cm, then a few feet, then meters!) if I don’t think about it, but once a second unit is involved or any distance, metric comes naturally. Grammes and kg I have used for years, they seem not to get corrupted so often. I have never done my weight in “them other things, what, stones, wt* are they?). Gallons I have not used in 30 years.Fortunately I have found the “Quest” TV channel which at the moment seems to use almost exclusively metric for its’ new productions. True the older ones with inclusive commentaries still use the old stuff, but for the most part I can watch an American video with metric commentary, just great!

I still genuinely totally fail to understand why any sane person chooses to continue to use such nonsense when a fully integrated co-ordinated proper system is otherwise used world wide. True we are stuck with decimals to base 10, but that is across the board. Those that say 12 inches is to a base other than ten are talking nonsense, 12 is a base 10 number, always will be unless you add the two extra digits so 12 = 10.

David says:
16 January 2013

Computers “think” in binary –
“there are 10 different kinds of people in the world – those who understand binary and those who don’t”

From “words” containing 4 bytes and bytes with 4 “bits” (binary digits) through octal and on to hexadecimal numbers the simplicity of the machine which controls everyone’s lives today revels in celebration of not understanding the dots and commas which separate into hundreds and thousands (or thousands and hundreds in a different part of europe) rather than integrate.

Only by a fundamental understanding of different bases could we understand the world and the way it works (ice crystals would be very flattened if made to have ten sides).
The names by which different bases are recognised is to allow communication between us but the bases themselves have each their own lives and purposes.

Long may they live.


That takes me back to the 1980s when well meaning people thought that we should all understand a bit about how computers work and that it would be a good idea to learn BASIC. Though I went along with this, I can’t help feeling that those who waited until it was easy to do word processing, send emails, use digital photography and order things online might have made better use of their time.

I agree, that our young people, should learn different numbering systems, other than base 10. However numbering systems, are different from measurement systems. They are not the same. Some people have suggested that Imperial measurements, should be retained as an example, of a base 12 numbering system. However Imperial measurements are not base 12 and are a poor example and should not be used to teach the base 12 numbering system.

I agree that computers think in binary. However the human interface, the input/output that we use when using the computer is alphanumeric, part of which is the base 10 decimal system which we are all familiar with.

@wjg and others. If you are referring to my post above, you seem to be confusing systems of numeration – how numbers are represented using a set of symbols – with the operation of numerical systems – how a person or device works with numbers, i.e. “does the maths”. They are different.

The Roman’s used I, II, III, IV, V, VI etc. as their system of numeration. This is how they **wrote down** numbers. It also happens to be a notation that fitted well with the use of a standard abacus, normally a bi-quinary device, having 4 beads in the lower register and 2 beads in the upper register.

Even some early computers, including Colossus used a system of bi-quinary computation. This doesn’t mean they output their results in Roman numerals! Today’s IBM mainframes have machine code instructions that operate directly in decimal (base-10) mode as well a binary. The output almost invariably uses decimal notation in both cases, but get it wrong behind the scenes and the calculations and program logic could be rubbish.

There is an early example of a Roman abacus that operates using bi-quinary for whole numbers, but the fractional columns have an extra bead in the Ө position, allowed for the counting of 1/12 of a whole unit called an uncia. Guess where the English words “inch” and “ounce” derive from.

As the example above shows, it doesn’t folllow that a numerical system needs to use a single base or radix, although you would probably get confused if the results used multiple number bases for displaying the results. In fact, you probably have a device in your home that operates using base-60 computations, and is also switchable between base-12 and base-24 computation, but since it only outputs using decimal notation, you might not recognise it as a digital clock.

Finally, there is no “poor” way to teach someone a concept. I defend absolutely the right to help a person who just doesn’t get it using the prescribed wisdom. If necessary I will resort to finding some example or analogy they can identify with, that helps them to overcome a blockage to their learning.

This reminds me of a news story I read last year in the Metro, which has a policy of using metric in all their news stories and quoting imperial in brackets. It reported a CAA statement that “the aircraft was cruising at 11000m (36089 feet)”. This shows the stupidity of the reporter. Aviation in the UK uses feet for heights, so the CAA would have given their original statement as “36 thousand feet”, then the newspaper converted that into metres (reasonably rounded to 11000) and the writer then converted it back into feet. This highlights a lack of education in maths: it is not only the figure that matters but also the precision. If you don’t really mean to say that every foot of height is significant, then don’t say it. So my suspicion is there is something lacking in the maths taught at schools even before we start to debate whether to teach imperial or not.

Let’s consider this in a different way, Clint. If the editor of the Metro allowed feet in the aviation story but used metres elsewhere they would deserve criticism for lack of consistency. So the writer has used metres and give feet in parentheses, but rounding of the numbers could result in letters from pedants pointing out that 11000 m is not the same as 36000 ft. It is not easy for the newspaper reporter.

My own preference would be to say that the aircraft was cruising at a height of 11 km (approximately 7 miles) because I’m a scientist and avoiding unnecessary zeros helps prevents mistakes.

The aircraft may not have been flying at exactly 11000m, so rounding both the metric and imperial values would have been acceptable. Pedants beware. We are familiar with altitude expressed in metres or feet, so changing the familiar units can be unsettling.

I used to work with someone who was well qualified and very logical, yet whenever he made calculations he expressed his results to a precision that was quite unwarranted. He was possibly a scientist rather than an engineer.

There is a word for this in the dictionary, “approximately”. While I am very much in favour of using all metric, when it comes to conversions from something which is a defined specification (i.e.car wheels), then care and knowledge need to be applied. Flight level 360 is just that. To suggest the pilot is flying at any other level could be libellous, especially if an in flight incident is involved. In the above example “approx 11,000 m, (36,000 ft)” or “approx 11 km, (FL 360)” would seem better. If it is in metric air space it remains metric.
On a more down to earth example, a 5/16 inch UNC bolt for an old car cylinder head is a 5/16 inch UNC bolt, it is not 8 mm, which is a metric thread and will not (well, it will!) fit. It could be “7.9 mm, (5/16″ UNC)”. Having been caught out on this one myself, quite expensively, I feel just adding the UNC,UNF,Whit, BSF or metric would remove all doubt and confusion.
A genuine plea to Which? There, to take that one up, my local MP was less than helpful. The reply from the minister no less seemed to be, we sympathise, but that’s the way we like it, hard luck.
There are loads of these examples, plastic pipes is another one. Copper (supply) pipe is covered by law, plastic (outflow) pipe it seems is not).
Am I alone on this one?


Significant figures, precision and accuracy are things that many scientists are rather obsessed about.


Flight level is not precise. It is “just a number”, a barometric pressure relative to 1013.25 hPa, what matters is that all aircraft use the same level. It is not height, it is not altitude it is flight level. Precision guesswork is not really my thing.

Wavechange – agreed, the significant figures in the result should reflect the accuracy with which the measurements have been made that are used in its calculation. Unwarranted mathematical precision is misleading.

I like precision calculations on estimated variables, so long as all odds remain even and all variables remain constant.

Brian – I think you will have to try harder than that to gain a reputation for smart comments. 🙂

IrvSwerve says:
18 January 2013

This Conversation has sunk into the sands!
To jazz it up a bit does anyone know if farmers
still refer to “acres ” or regularly use hectares?
How many of the general public can even describe
what a hectare is?
Finally does anyone know the historical reason
for an acre being equal to 4840 square yds?
An area of 4900yds = 70×70 would make more

This member of the public knows that a square 100 x 100 m is a hectare, making it 10,000 square metres. An acre is approximately 2.5 hectares. I rarely have any involvement with land areas, so don’t have much feeling for them, and I have no clue about their history.

My guess is that farmers are able to switch between metric and imperial units, but let’s await an answer to this interesting question.

PS Why is the length of the lines so short
in your postings, IrvSwerve?
Argonaut of the Seas used to annoy us
by doing the same thing. Are you using
a Commodore Vic 20 or a Sinclair Spectrum. 🙂

An acre, I believe, was the amount of land that could be ploughed in one day by a single plough, possibly pulled by oxen. Like many “old fashioned” measures, it was based on a practical scenario.

Malcolm r is correct.

An acre is based on a strip of land measuring 40 rods x 4 rods or 160 square rods. A rod is 16.5 feet, so the above area is equivalent to 220 yards by 22 yards = 4840 sq yards.

Why 40 rods? It’s a furlong (a furrow-long), the amount of land a team of oxen could plough without resting. An acre being 4 rods wide suggests that the team could plough 4 furrows a day with natural breaks in the morning, lunch and afternoon.

Why isn’t it based on a square piece of land? Because turning the plough and oxen was time-consuming. Better to work in long, narrow strips.

Thanks for that, Malcolm and Em. It’s a lot more interesting than the Greek mythology that I was taught at school, though Greek mythology is more useful if you are watching University Challenge.

Errrm, em,

That is the best example I have seen yet as why NOT to re-introduce Imperial into the school curriculum.
I wonder if Gove and co have any idea.

@BrianAC – So fathom this one:

The ISO (metric) standard for A4 paper stock is 210mm x 297mm. Why isn’t it 200mm x 300mm, in the same way that US Letter is an easy-to-remember 8.5″ x 11″?

There are two perfectly good reasons for this that I’ll let someone else explain, but it’s not exactly intuitive, is it?

I believe that the A0 size has an area of a square metre and – as is better known – each step in the series represents half the area of the previous size. I have always regarded this as quite useful. The fact that a sheet of A4 copier paper weighs around 5 g makes it very easy to estimate the number of copies in a pile. I have never given much thought to where the term ‘ream’ comes from, but pack of 500 sheets (the current interpretation of a ream) is a convenient number.

Just a quick correction. “An acre is approximately 2.5 hectares” Actually, it’s the other way around. A hectare is larger than an acre, and I suspect this could be a minor reason that a lot of British people are still using acres: aside from farming, some rich people have big houses with “gardens” spanning 2 or 3 acres. But a hectare is usually too large for this sort of measurement: it just doesn’t sound as catchy to say that someone’s house is set in “1.2 hectares” whereas “3 acres” flows off the tongue more easily.

And don’t get me started on paper sizes. The number of times our printer at work has got stuck waiting for someone to load US Letter-size paper (which we don’t have) just because someone tried to print a memo sent from the states. I wish the Americans would start using the same paper size as the rest of the world.

Well spotted Clint. That was carelessness rather than lack of knowledge but as I said I’m not familiar with acres and hectares and have to think about them.

Be grateful that foolscap paper had disappeared before we had office printers.


A higghly entertaining read that answers all. Who knew our shoes sizes used barleycorns!

Em wrote: Finally, there is no “poor” way to teach someone a concept. I defend absolutely the right to help a person who just doesn’t get it using the prescribed wisdom. If necessary I will resort to finding some example or analogy they can identify with, that helps them to overcome a blockage to their learning.

I can identify with this, having helped many science students overcome problems with calculations and working with unfamiliar units. It certainly does help to use introduce familiar examples and simple analogies. Starting off with integers rather than numbers with decimal points can help many learn concepts. One of the most satisfying experiences for me was to see a student help others do the calculations that they had struggled with earlier. It does not worry me that different people handle numbers in different ways providing that their calculations are correct. Over the years I have learned the common conceptual difficulties, but that different approaches are sometimes needed.

I am very glad that I never had to deal with imperial units in science teaching.

Thank you for your contribution wavechange. I did teach physics, so SI was my lingua franca, but I now practice in, and sometimes lecture on, computer systems including digital publishing. This is still based on Imperial measures; points (1/72″), lpi (lines per inch), etc., regardless of what some people might think.

The Wikipedia article on measurement has some words that sum it up nicely for me:

“With the exception of a few seemingly fundamental quantum constants, units of measurement are essentially arbitrary; in other words, people make them up and then agree to use them. Nothing inherent in nature dictates that an inch has to be a certain length, or that a mile is a better measure of distance than a kilometre. Over the course of human history, however, first for convenience and then for necessity, standards of measurement evolved so that communities would have certain common benchmarks. Laws regulating measurement were originally developed to prevent fraud in commerce.”

It’s possibly because of the last point that people associate measurement with politics and get worked up. Metric time, anyone? For some reason it didn’t catch on, even though it was brought to you by those nice people who thought the Guillotine was the answer to anyone who didn’t subscribe to their doctrine.


I learned about this when I acquired a CP/M computer and one of these new-fangled dot matrix printers. Then it was pixels per inch when working with early DTP and image manipulation software. Computer screens are another example, so we have the Apple retina display at over 200 pixels per inch.

I presume we are all using the same system and if so, there may be little need to change.

>>> I presume we are all using the same system and if so, there may be little need to change. <<<

Nearly every DTP / display / printer combination is different, which is why it is essential to use the correct drivers for each component in the system.

MS Word uses twips – 1/1440" – internally, but points, inches, centimetres, whatever, for input and converts it. A typical printer uses 300 or 600 dots per inch. One printer protocol uses a resolution of 1/240" for some measurements, 1/1440" for others, and allows you to define your own units based on a sub-division of 10".

Needless to say, I was a little disappointed with one work-placement student who had no concept of what an inch was!

From the Web

“The metric system was first legalized for scientific use in 1864. Then in 1871 the House of Commons proposed to make metric the only legal system for all purposes, but the proposal was defeated by only five votes. It was not until 1897 that the metric system made legal for trade as well.

In 1947 Prime Minister Clement Attlee commissioned a study on the future use of metric units in the UK. A resulting 1950 report stated that the metric system was a superior measurement system, and would eventually become the norm, but that the UK should wait until the Commonwealth and North America converted, as these were our main trading partners. Business was unenthusiastic about the metric system for this reason.

The British Standards Institution produced a survey in 1963 which indicated a significant majority of industry favoured metrication. In 1965 the Government announced support for metricating the UK within 10 years. The Government established the Metrication Board in 1969, to help industry go metric in an orderly fashion. It was hoped to have the metric transition largely in place by 1975, but that provision could only be made for certain sectors of the economy. In 1980 the Conservative government came to power, with little enthusiasm for metrication or legislation, and it dissolved the Metrication Board, but by 1980 many sectors of industry had already gone metric.”



Not only is A0 1 sq m, but the sides are in the ratio 1 to square root 2 (about 1:1.414, or 0.7 to 1). So the subsequent sizes – A1, 2, 3 etc are all formed by taking half the larger size (folding in half if you like) – halving the area and preserving the proportions.

You mean to say there is a metric standard where the sub-multiples aren’t decimal? I’m shocked!

Binary scores on the doors: wavechange 1/10 (for not mentioning constant proportion) and malcolm 10/10.

Sorry I have failed but working in biological sciences has encouraged me to become sloppy. I have a lot of respect for mathematicians and physicists but it has been very interesting to move from chemistry towards biology, biochemistry and microbiology.

By the way, does anyone know if this site will accept standard HTML codes, for example to insert indices.

Hello Wavechange, it may do. We don’t really encourage it, but you can give it a go. If it doesn’t work I can remove your comment.

E = mc2, albeit off-topic.

I can understand why you don’t encourage use of html codes, so I will try not to experiment.

I do wish that there was a preview facility (as with many discussion forums) because I am good at spotting missteaks after hitting ‘Submit’ and the automatic spelling correction is not always very clever.

REAM – derived from European words apparently that mean a bundle. One ream is 20 quires (25 sheets). Which raises another………..

Yes, I looked this up after posting my comment. I’m guess that this sort of information was what we used to have on the covers of exercise books in the dark ages, decades before Wikipedia arrived.

Ask any youngster their height and it is always in feet and inches. Ask any driver of whatever age what speed a car is travelling it will be in miles per hour.. Ask any Mother the weight of her new born baby and she will quote pounds and ounces. Go to weight watchers and the measurements are in Stones and pounds. Televisions screens are measured in inches.
I work for an Industrial clothing company and we have reverted back to imperial measurements for chest and waist sizes and leg lengths because no one knew what the metric equivalent is. In fact we no longer put the metric sizes alongside the Imperial measurement in our catalogue or the product itself..

Here are a few problems with the metric system to consider.
1) 25mm is an Inch. and lets say a metre is a yard but where the metric system falls down is that there no direct.equivalent for a foot, So you would never hear in everyday conversation such as,62 centimetres of snow fell last night as opposed to two foot of snow.62 centimetres does not exactly I roll off the tongue does it?.

2) As long as we trade with the United States many manufacturing companies will still have to work in Imperial measurements.so all these Europhiles will never completely eradicate the Imperial system

3) If it is mentioned on for example a T.V documentary that Mount Everest is 8,850 metre in height the scale of it is diminished when you give the Imperial equivalent 29,352 feet which to my mind gives me some idea of it’s scale 8,850 metre to my mind is like a small hill in Lincolnshire.

4 )Have you ever heard a song with the word Kilometres/metres millimetres or kilos in it? No neither have I. Just does not rhyme. The late great guitar Legend Rory Gallagher penned a song called Country Mile. Even the most pendantict Europhile would admit that it would not work if it was renamed Country Kilometre (or whatever metric equivalent to a mile is)

5) Every year I go to the south of Ireland for my holidays a country who have embraced all things Europe……in order to gain massive subsidies. All their road signs are now in kilometres and imperial units are a thing of the past……..on paper anyway. I have never heard an Irishman use the word Kilometre to describe how far away some place is. Henry street market in Dublin all the fruit and vegetable stall holders sell their produce in pounds and pretty much every bridge height is still marked in feet and inches.

I have tried to embrace the metric system believe me I have, but much like Mushy peas It does not agree with meal though I will be the first to admit that working in millimetres is better than working in 7/8ths or 15/16ths of an inch. but i have to keep onverting metric back into ‘English’ I do know that 600mm is two foot but I do not know how many centimetres that is!

Enough from me. I feel the need for a treat so I am off down the local confectioner and will be asking for a ‘quarter’ of dolly mixtures. Actually sweets are so small nowadays that they will have to be measured in millimetres.

jraf Hmmm!

So, you have tried to embrace the metric system, you know that 600 mm is 2 ft, but don’t know how many cm that is?

As I have said many times before, it is not the metric system that people have a problem with, it is a very much more basic problem of not understanding decimals, the very basis of the entire world numbering system.

That is sad.

jraf@ Im pleased to read that you have tried to embrace the metric system. Some people do not try at all, and find themselves lost, and increasingly frustrated, in an enviroment that will ony become more metric. There are many metric sites on the internet, some better than others, and I suggest that you find one that explains metric in easy to learn stages.
However as a start I suggest that you make yourself familiar with these three metric prefixs.
milli is 1/1000 and is m
centi is 1/100 and is c
kilo is 1000 and is k
In length/distance 1 millimetre x 10 = 1 centimetre x 100 = 1 metre x 1000 = 1 kilometre.
In weight/mass 1 milligram x 1000 = 1 gram x 1000 = 1 kilogram.
In volume 1 millilitre x 1000 = 1 litre.
Also the metric system is human in scale..Someting that you can relate metric measures to..
The lengths of most people’s feet are close to 250 mm. Therefore there is about the lenght of four human feet to one metre. (250 mm x 4 = 1000 mm = 1 metre).
Your hand is about 100 mm across if you include your thumb.
For most men the width of their little fingernail is close to 10 mm.
For most women the width of their fingernail on their long finger is close to 10 mm.
Your hand span is between 200 mm and 250 mm.
Women’s walking pace (step) is about 500 mm.
Men’s stretched walking pace (step) is about 1000 mm or 1 metre.
A marching pace (step) for both men and women is 750 mm.
Most people walk at about 100 metres per minute.
If you walk briskly for an hour your will walk 6 kilometres (6 km/h).
The body mass of most women is between 50 kg and 80 kg.
The body mass of most men is between 60 kg and 90 kg.
The average height of men is 1.75 metres.
The average height of women is 1.65 metres.
Most newborn babies are close to 500 mm long.
I hope this helps.

w j g:
“The body mass of most women is between 50 kg and 80 kg.
The body mass of most men is between 60 kg and 90 kg.”

P.S. If you are reading this in the US, please double the above figures.

Hi clint kirk, please stick to our commenting guidelines and bear in mind that some people may find your comment offensive. Thanks!

My apologies. No offence intended.

As you say, Jonathan, the calorie has a “large and small variant” though to be exact, since a “large calorie” is 1000 “small calories”, it should just be called a kilocalorie. And sometimes you see that term used.

We have the food and diet industries to thank for this bit of confusion. When diet people talk of “counting calories” they really mean “counting kilocalories”.

However – there’s no need to “metrificate” (aaagh – does that word even exist?) the calorie (or kilocalorie). It’s metric already as proved by your definition of “energy required to heat 1g of water by 1K”. However, it’s a poor choice for representing energy as the energy/temperature curve for water is non-linear and so you have to specify the starting-temperature of the water as well.

Quite a few food labels these days quote the energy content of foodstuffs in kJ (kilojoules) which is a much better system to be using. The government was, I believe, investigating whether kJ should be mandated for labelling at the same time they were looking at ideas like the “traffic lights” food labelling ideas. I don’t know what became of all that…..

Might I suggest that “Which?” should be taking a stance on this issue (I know you’ve been championing the traffic lights labelling, but what about kJ??).

A switch to kJ would certainly be better for consumers than the confusing calorie vs. Calorie vs. kilocalorie (i.e kcal) mess that we’ve been saddled with by the idiot diet industry. Just wait – they’ll bring out the kCal to further mess with our heads next!

All we need is Joules (and kJ and maybe MJ). Worth considering, “Which?” ?

Or do you already have an opinion?

Re: Jref’s original posting:

“Here are a few problems with the metric system to consider.
1) 25mm is an Inch. and lets say a metre is a yard but where the metric system falls down is that there no direct.equivalent for a foot, So you would never hear in everyday conversation such as,62 centimetres of snow fell last night as opposed to two foot of snow.62 centimetres does not exactly I roll off the tongue does it?.”

If 60(ish) cm of snow fell, I’d expect to hear it referred-to as “60cm of snow fell last night” on the news (or wherever). That’s not a “problem with the metric system”, it’s just how it is. What do you think would be said on the Japanese news, or the Russian news about such an event? Yeah, they’d say (in their own languages) that 60cm of snow fell. Just like the news a few nights ago pointed out that they’d had 30cm of snow in Merthyr Tydfil that day, with more expected.

“2) As long as we trade with the United States many manufacturing companies will still have to work in Imperial measurements.”

That’s not a problem with the metric system, that’s a problem with the Americans!

“….. so all these Europhiles will never completely eradicate the Imperial system”.

Europhiles? Where did they come from? What do europhiles have to do with the metric system? Metric may be the system used across Europe, but Europe doesn’t own it. What about the people of China? Of India? Of Australia or of Japan? Of Russia? None of those places are Europe or likely to contain any of your Europhiles!

“3) If it is mentioned on for example a T.V documentary that Mount Everest is 8,850 metre in height the scale of it is diminished when you give the Imperial equivalent 29,352 feet which to my mind gives me some idea of it’s scale 8,850 metre to my mind is like a small hill in Lincolnshire.”

That’s not a problem with the metric system, that’s a problem with you!

Ordnance Survey maps have had contours in metres since the 1970’s and all the original surveying work for those maps (done in the 1930’s) was done in metric even back then. That’s why the national grid is in kilometres – or hadn’t you noticed? As for Everest – if it is 8850m high, then it is also 8.85km high, which is obviously nothing like any “small hill in Lincolnshire”.

Clue up, man! Try living with everyone else in the 21st century. Don’t just assume that a mountain height is automatically in feet when (as I said) the maps haven’t been like that for more than 40 years. You don’t still assume that a price in the shops is in £sd do you? You don’t still watch 405-line black-and-white television do you? Your mobile phone (assuming you’ve got one) doesn’t have an aerial sticking out of the top does it?

Nice reply Swansea Steve, however,

“2) As long as we trade with the United States many manufacturing companies will still have to work in Imperial measurements.”
That’s not a problem with the metric system, that’s a problem with the Americans!

a) The Americans do not use the Imperial system, this is a common mistake, they use U.S. Customary. Those units which are the same are often used differently (we used to use ft-lbs, US uses inch-lbs, our torque wrenches would never be used). USA would understand little of the way we use the same units (or used to use).
b) Most, if not all, export import trade conducted by USA is conducted in metric , not any other units. Except in this they manage to export a lot to UK because people in UK don’t know it is useless over here!

Thanks for your comment Swanseasteve. We want to encourage everyone to share their opinions, so please try to be polite to each other while having a debate. Thanks!

Stimpy says:
23 March 2013

@jraf: “3) If it is mentioned on for example a T.V documentary that Mount Everest is 8,850 metre in height the scale of it is diminished when you give the Imperial equivalent 29,352 feet which to my mind gives me some idea of it’s scale 8,850 metre to my mind is like a small hill in Lincolnshire.”

I’ve never thought about this in depth (so to speak) – that mountain is in the zone of 747’s etc!

Not trying to encourage it or anything like that, heaven forbid, but, interestingly enough, even the Europeans sometimes use inches. For example, see this French TV advert:


“Téléviseur LCD 46’’ à 52’’”

Having been educated with both systems, I prefer using metric for giving exact specifications but I still use imperial for casual everyday speech when precision is not necessary. Sometimes I would treat an imperial measurement more as a name for a size rather than an exact measurement. For example, when I need tyres I ask for 205/55W16. The 205 is in mm, the 55 is a ratio (therefore a number with no units), the W is a code for speed, and the 16 is in inches! So every part of a tyre size is in different units, but I don’t care, as long as it fits my car. Also I don’t know or care if the 16 inches really are 16 inches or perhaps they are actually 15.7 or 16.2 and they call it 16 for brevity, as long as they use the same convention for tyre and wheel rim sizes. But I expect the 205 mm to be a more precise measurement of the actual width.

IrvSwerve says:
22 January 2013

Jonathan,you’re causing more confusion!
As “any skuleboy noes” or used to in my day
the calorie IS metric & according to Joules Law
4.2 joules= 1 calorie.
As you say the food energy measure is the Calorie
which equals 1000 calories.

I believe that kcal has largely replaced the Calorie on food packaging, though I doubt that anyone confused them.

Those on a diet might prefer kJ to kcal because they can have over four times as many. 🙂

Of course the metric system originated in Europe – the basic theory was proposed in 1668 by John Wilkins, sometime Bishop of Chester, and the concept of coherency, one of the basic premises of SI by James Clerk Maxwell. Edward White in 1599 proposed using the earth’s meridian as the basis for an internationally-recognised unit of length and Latimer suggested naming certain units of measure after various people and the firm Johnson Matthey manufactured the international prototype kilogram which is still in use.

The was assistance from outside Britain, Simon Stevan (Dutch) promoted the use of decimal number, Mouton (French) proposed a standard set of names for metric units. The French Government actually introduced the metric system while successive British politicians appear to be doing their best to undermine the work of British scientists.

IrvSwerve says:
22 January 2013

This a question for any Aussies out there,who of
course are completely metrified.
Off the top of your head,what is the length of a
cricket pitch. No calculating, as this is your
national game you should know this automatically.
(Here’s a clue.In the UK it’s one chain)

I make it 20 metres 4 1/2 inches

But it’s not cricket to mix units in this way. 🙂

My calculator says it is 20 m 4.5984251 ins

As Jonathan has stated, the calorie is confusing because it has a number of definitions.
It is defined using the metric units ..gram, (or kilogram), kelvin, and kilopascal. However the calorie is a metric unit, that comes from the centimetre-gram-second (cgs) era of metric development. It is not a modern metric (SI) unit. The modern metric (SI) system, has only one unit for energy and that is the joule.
Interestingly, the UK Department of Health, is still considering if kcal, or kJ, should be the energy unit on the nutritional labels, on packaged food. I have recently been in Australia, and on their nutritional labels, kilojoules are manditory, and kilocalories can be supplementary.. They have set the standaed that we should follow.