Understanding body weight and height in metric units

It was inevitable that the selection of London to host the Olympic Games would bring into focus some of the consequences of the UK’s measurement muddle. Metric Views looks at one aspect, the measurement of body height and weight, measured in metric for athletes, and in imperial for many others following the custom of previous generations.

When asked, we in the UK will usually give our weight in stones and pounds and our height in feet and inches. You may wonder what is wrong with that and why we ought to express our height and weight in metric units. After all, feet and inches are used in the US, and, although stones are now used only in the UK, it is not too difficult to convert them to pounds (so long as you remember how many pounds to a stone – now is that 12 or 14 or 16?)

Equipment at gyms commonly uses kilograms, the NHS works exclusively in metric units and our Body Mass Index is based on metric units. If you ever need emergency medical treatment abroad, it would be useful to know your weight and height in metric units as paramedics may need it. It is also easier to do calculations in metric units.

Familiarity with measurement units comes with usage. Despite the fact that the NHS and the Government work in metric, they feel that it is necessary to provide conversions when communicating with the public, thereby delaying public acceptance.

The average British man weighs about 84 kg and is about 1.75 m (or 175 cm) tall. The average British woman weighs about 70 kg and is about 1.62 m (or 162 cm) tall. The average length of a newborn baby is about 50 cm, and it weighs between 3.0 and 3.6 kg.

The Body Mass Index (BMI) is calculated by your weight in kilograms divided by your height in metres squared. A normal BMI is between 18.5 and 25. Someone with a BMI below 18.5 is underweight. Someone with a BMI between 25 and 30 is overweight and any BMI above 30 is an indication of obesity.

Here are some facts about people’s weight and height from The Guinness Book of Records . Robert Wadlow is the world’s tallest man in history at 2.72 m. Yao Defen is the world’s tallest woman in history at 2.33 m. Chandra Bahadur Dangi is the world’s shortest man in history at 54.6 cm. Pauline Musters is the world’s shortest woman in history at 58 cm. The heaviest person on record was Jon Minnoch who weighed at least 635 kg. And Wikipedia tells us that Usain Bolt, World and Olympic 100 metre record holder, is 1.95 m tall and weighs 92 kg.

Experience suggests body measurements are among the last of the old measures to be dropped. In a visit to Denmark in the late 1950’s, about sixty years after the metric changeover, I met no one who used old measures for body height and weight, whereas, during recent visits to several Commonwealth countries, I met a few who had not made the change. Perhaps the Olympics in London in 2012 will help the UK to make progress. They may also demonstrate the value of the familiarity that comes from using a single system of measures for all purposes – is Mr Bolt really that much taller than me?

20 thoughts on “Understanding body weight and height in metric units”

  1. As a Brit living in Australia, it’s interesting to note that – even among people who went to school long after the 1970s changeover here – height is still generally expressed in feet and inches. It’s pretty much the only measurement that is, at least among people in their 30s and younger.

    I heard recently that the NHS gives new parents their baby’s weight in pounds and ounces, and not in kg. That’s pretty appalling if true (although food-style dual measures would be acceptable, for communication to grandparents etc…)


  2. Interesting to hear that John B.

    I am always pleased to see on the ‘Biggest Loser – Australia’ (which is broadcast here on the News Corp Sky network) that Ossie people are so familiar with their weight in kg.

    There is a current trend on UK TV for programmes featuring families moving to Australia or NZ. The scenario is that they are flown around the world to try out the new lifestyle. A lot of the workers are in trades such as plumbing, electrical etc and none of them have ever thrown their hands up to say ‘oh no, its metric I can’t cope with that!’

    I do despair over the ‘baby weight’s’. Yes, the NHS do measure weights in metric, but always give that in ‘old money’. I thought we’d turned a corner when a recently born baby within my partners family was reported to have gained ‘500g’, but all the comments on their Facebook that followed were of the ‘whats that in English’ variety – very depressing. :sigh:


  3. Ronnie – Interesting to read in your article about the facts from Guiness World of Records in metric. Is this how they quote them, or have you made them the conversions yourself? The reason I ask is that I have just emailed them following a report on the BBC referring to the tallest wave to be surfed by a human being. This referred to variously in the media as being ’90 feet’ (BBC) or 30m in the Portuguese press, and 27m in the Canadian press! What a mess!


  4. Interesting info about Australian usage of Imperial for height. What do younger folks use for expressing their mass (weight)?


  5. @john b
    I envy you being in a country that is ahead of us in the UK when it comes to measurement. However, speaking as someone who has recently become a grandparent, I do not wish to be used as an excuse for us delaying the switchover to metric.

    My daughter was born in 1980, and her weight was given as 3.2 kg (easy to visualise : 3.2 bags of sugar). Yet when her son was born 2 years ago the baby’s weight was given in these new fangled pounds and ounces (what common household object can I compare 7 lbs and 13 oz with?).

    I think people forget that metrication began at least 2 generations ago. There is no need to be using obsolete units just for us “oldies”.


  6. In answer to Ezra’s question: I’m a 64 year old Brit who has lived in Australia for 22 years. Everyone here expresses their weight in kilograms. People of my age can sometimes remember their weight in imperial measurements (I can’t) but rarely say it for fear of ridicule. Young people have no idea about pounds and stones. However, people around 30 years old, despite being fully aware of their height in metric units, often refer to it in feet and inches. I think this is partly to appear more mature and partly because of the influence of popular American TV shows and films. I was shocked when my 30 year old niece who was visiting from England told me she had no idea of how much she weighed in kilograms or how tall she was in metric units.


  7. I’ve lived in the USA for many years but I have continued to weigh myself in kg, measure my height in cm and read my body temperature in C. My GPS talks to me in km and m. All this in spite of having grown up with feet and inches, stones and pounds and Fahrenheit temperatures. The metric conversion in Australia was so smooth and so complete that I never wanted to go back, even after moving to a country which even today refuses to acknowledge the metric system.

    I do note that some of the major hospitals in New York are exclusively metric except when speaking to patients. The nurse will record a temperature as 36.4 but will tell the patient 98, record a weight as 82.6 but speak 182.


  8. It is indeed a great shame that there is such a strong adherence to stones and pounds for body weight in the UK.

    I have been monitoring my weight closely for the past 6 months as I am in the process of reducing body fat. The kg has a lot to offer here. It is much easier to calculate percentage loss and do the arithmetic generally for assessing progress and forecasting how long it will take to reach my ultimate goal.

    On this point it is quite significant that the UK public are now being told that a modest 10% loss would be of great benefit to people suffering obesity and worth doing. Surely an added incentive to start using a better system of units for measuring it.


  9. My Canadian citizen card says I am 177 cm tall – but that was in 1978. A couple of months ago I visited my NHS doctor, and he measured my height – I am now 174 cm tall. I’ve shrunk by 3 cm over the last 35 years. My scales say I am 67 kg – so my BMI works out to 22.13. I am happy with that.

    The real issue though is that I come across people measuring their height in cm all the time (and I know the late Pat Naughtin would take issue with that, for not using mm), but it seems so easy. Quite why the populace (even in Australia) clings to the so-incovenient ft and in completely escapes me.


  10. I think that part of the reason that Australians know their weight in kilos but often give their height in feet and inches was that at one time the law prohibited the importation of non-metric scales. However, there was a revolt when the government tried to ban the importation of rules that had Imperial or dual markings. Therefore the old measures continued to be used for height and weight.

    But there’s another reason. Adult weight fluctuates, but height is relatively stable. To know your weight you have to measure and remeasure it, even if your weight is stable. However, for height, you don’t have to remeasure for decades. That is an important reason why the old measures cling so much more to height than weight.


  11. Despite being metric educated I do recall from a relatively early age wanting to express my height and weight in imperial because, despite what I was taught at school, it was the “normal” thing to do. However for many years I always struggled to remember what my weight was in stones, mainly because I had no concept of what a stone is in relation to everyday objects (probably because nothing else is ever weighed in stones!) and for many years never even bothered to weigh myself.

    Then about 10 years ago I made a conscious decision to use metric… and haven’t looked back. I now fully understand my physical dimensions and how they relate to my health and the food I eat. About 8 years ago I purchased metric-only weighing scales while in France, anybody who wants to weigh themselves in my home now has little choice and it’s caused no problems.

    I do still grimace when friends use imperial, even friends in the forces seem to switch erratically from stones to kg. On the whole though I’ve found that a lot of people will use metric if encouraged and I don’t encounter many people who actually get upset at my use of metric.

    If only the press and TV would use metric by default we’d probably find that imperial would soon disappear.


  12. I remember an article on this way back in the early 1960’s I guess. Probably in the ‘Daily Mirror’.
    Then they used a typical miss UK figure and gave all the vital statistics in metric units. I think they did much the same with food and drinks.
    No fuss back then, the press and public were pretty much in favour of metrication. Unfortunately the government were more interested in the Atlantic bridge than the UK.


  13. I notice that RT (Russia Today), Channel 85 terrestrial, has taken a common sense approach to weather reporting and gives temperatures around the world (every hour or so) in Celsius and farenheit – so one can take one’s pick.

    When I was at school, a long time ago, we learnt metric and imperial and had to be able to convert from one to the other – without a calculator. Perhaps it helped to make us smarther than the output from schools today, i.e. we learnt to think.


  14. Dave Barnby: I also learnt imperial at school but acquired metric very quickly living abroad. There is no doubt to me that metric is by far the more user-friendly system of measurement. However, even if it is challenging to convert between the two systems, do you not think that mental skills today are far better deployed learning something more useful to life in the 21st century?


  15. Dear Dave

    It is hard to dispute that if young people have to do more mental arithmetic it will give them more practice but there are other ways beside having to cope with awkward and inefficient measurement units. I would also question the claim that it teaches people to think – mental arithmetic is only of value if it consolidates an understanding of the principles – much of arithmetic is mechanical.

    If there is any connection between a perceived fall in educational standards and the changeover to metric in schools it is much more likely to have been caused by the failure to change the rest of society at the same time. As it is kids at school must find it difficult to consistently apply their learning outside lessons, which is a crucial part of the process.


  16. One way to encourage people to switch to metric measures for height and weight would be to encourage football clubs to express the players’ heights in metres and their weight in kilograms. It has already happened to a certain extent. For example, the Premier League and the BBC give this information in metric measures. So do a few individual clubs. The job that remains to be done is to persuade the rest of the clubs to do the same.


  17. On a visit to the local surgery for the flu jab I was given a personal data form to fill in. As expected the height and weight was ft-ins and st-lbs first. The metric equivalents were height ….. cms and weight ….. kgs. Now this together with other issues of being given ‘English translations’ whenever I have presented my weight and height in metric, I do wonder just how far the NHS really has progressed to being fully metric.
    The message is quite simply not getting through.


  18. To follow BrianAC’s comment, I also had a personal data form to complete when I went for my flu jab. The form had no units for height or weight so it was up to the individual to decide what to use. No doubt most patients used feet and inches and stones and pounds.
    Why not request patients to use metric as that is what the doctors require?
    I spoke to my doctor about this and she expressed frustration with the need to convert.


  19. Hugh Fearnley-Whittingstall’s latest crusade – against obesity – includes a campaign to get the citizens of Newcastle to collectively lose 45,454.54 kg. Oops – 100,000 lb.
    What a wasted opportunity to educate the public about the application of the BMI. Surely as a chef and farmer HFW must be used to metric measures?

    I’m reminded of an episode of This Morning, in which Philip Schofield congratulated a viewer on her weight loss in imperial – and then gave the equivalent in bags of sugar!


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