Why do so few Britons use kg for body weight?

Britons tend to use grams and kilograms for a lot of things, including cooking recipes, gym equipment, commercial products and retail sales. However, they predominantly use stones and pounds for weighing adults and children and use pounds and ounces for weighing babies. Few use kg despite the fact that the NHS uses kg internally for body weight and BMI calculated by body weight in kg divided by height in metres squared. And despite the large number of everyday basic food products you can find in supermarkets that come in 1 kg packages.

Whenever you express a baby’s weight in kilograms, lots of Britons demand a conversion to pounds and ounces and that is normally what is publicly reported for new-borns, especially royal babies, despite the fact that they are measured and recorded in kilograms. Officialdom tends to bow to popular demand and convert the kg weight to pounds and ounces. For children and adults, lots of Britons ask for body weight measurements to be expressed in stones and pounds. If you express your weight in kilograms, you will probably find many Britons who would want to know what that is in stones and pounds.

However, go to a typical supermarket and you find countless basic foods sold in 1 kg packages. Here are some examples:

caster sugar

chick peas

plain white flour


porridge oats



Food products in 1 kg packages

These are some examples of many basic food products sold in 1 kg packages. We pick them up and put them into our shopping basket or trolley without a second thought. Apparently, many Britons have felt unable to relate these 1 kg packs to their own body weight.

So why do so many feel unfamiliar with body weight expressed in kilograms? Why have many Britons found it hard to adapt to kilograms for body weights but had no problems adapting to the use of kilograms for food products, gym equipment and furniture?

Is it due to peer pressure, inertia or a desire to stick with what they are used to? Or a combination of all three? Metric Views is interested to hear from readers about this strange phenomenon.

21 thoughts on “Why do so few Britons use kg for body weight?”

  1. I say my weight in Kilograms, I currently weigh 88Kg, although I did weigh 97Kg, if people ask me my weight (rarely people ask) I say it in Kilograms, if they don’t like it (and nobody’s complaining about it) that’s not my problem. I just consider myself more advanced than people because I’m willing to adapt to the modern World..

    Liked by 2 people

  2. Royal Births: polite requests made by me, and by others for the Royal Household to change and make their announcements in metric have so far failed.
    When is the next Royal birth due to be announced?

    Lee Kelly – the correct symbol for the kilogram is ‘kg’ (lower case k, followed by lower case g).
    ‘Kg’ is an inkorrect symbol. [Just an important point when writing symbols for units.]

    Liked by 1 person

  3. Metricviewer:

    Did the Royal Household ever explain why they insist on using pounds and ounces when notifying birth weights, when they are only ever used officially as supplementary units in trade? (I happen to think they should stop being used at all in trade. It has gone on for far too long.)


  4. It’s the dichotomy between professional users of weights and measures and the general public. This dichotomy would never have developed if the change to metric units had been properly explained and implemented. It is now self-perpetuating and self-reinforcing: the media use stones and pounds routinely, so the ordinary reader relates to that. Change to metric and the reader or viewer will relate to metric units. It’s that simple.

    Liked by 1 person

  5. It really is frustrating for those of us who do use kg all the time. Just last week I had a medical checkup, I told the nurse that I expected my weight to be around 79 kg, she weighed me and proceeded to read my weight back to me in stones. It was just a normal thing for her to do.

    I also know vets work entirely in metric yet my step-daughter always tells everybody how fat her dog has got in stones.

    What I found most disturbing is my other step daughter and my daughter in law who have recently given birth talking about milk (both breast and formula) in ounces and I get the feeling that even midwives and health visitors may not be discouraging this practice. I really cannot believe in this day and age that non-metric markings are actually allowed, let alone exist, on baby bottles! It’s clear that if medical professionals insisted on using metric measures on the grounds of safety with new parents that the continuing use of imperial measures might fade away very quickly and I do think this is one area where legislation should be used.

    Liked by 2 people

  6. The reason the stones and pounds are used so widely is that the Heath and Wilson governments did nothing encourage the British public to use metric units – both were scared of losing a few votes which. in the British “first-past-the-post” system could mean the difference of being in government or not. In contrast, the South African and I believe the Australian Governments banned the sale of measuring devices that had imperial units on them. In contrast. in the United Kingdom, the press tends to use stones and pounds rather stupidly – for example I have seen press reports where the weights of large animals are quoted in stones – des anybody have a clue what 400 stones looks like? For the record, 400 stones is 2540 kg. My car, a Skoda Fabia weighs about 1200 kg, so I can visualise 400 kg as being twice the weight of my car. Also, since 1200 kg is 1.2 tonnes, I also know that it is safe for me to drive across a bridge that has a weight limit of 3.5 tonnes.

    * * * * * * * * **

    @metricviewer, @Lee Kelly

    The symbol “Kg” is a valid SI unit – it the unit for kelvin-grams. I am not too sure who uses this unit, but it is there in case anybody has a need for it. It could also be written “K.g”.

    Liked by 1 person

  7. @metricviewer

    The Royal Household is making an error in not using metric units when announcing royal births. His Majesty is not only King of the United Kingdom, but is also King of Australia, King of New Zealand, King of Canada as well as being king of other domains. Apart from the United Kingdom, most of his domains use the metric system. In order to be neutral in the metric-imperial debate, Buckingham Palace would do well to write “XXX’s weight was recorded as 3.22 kg (7 lbs 1½ oz)”. (The wording “recorded as” is a statement of fact). In order to be totally neutral, such statements should also be made in Welsh and in French (Note that both English and French are official languages in Canada).


  8. As an American I have always been confused by Britons using “stones”. Never could figure that one out. 😉


  9. It is a shame that so many British people persist with stones and pounds as it is such a poor unit choice. Not only is it not used for anything else or anywhere else for that matter of fact, even Americans just stick to pounds but it is also a ridiculous size given that it is about 6 kg. Making it a ridiculous size to meaningfully relate to body weight. It also makes calculation needless harder for a number of reasons. Never mind the bizarre cognitive dissonance of being fine using kg for other things but somehow struggle to comprehend it when it comes to human weight.

    Although I am noticing some inroads, it is still too little too late. More should really be made about the benefits of weighing in kg and general encouragement because they are needlessly making life harder by persisting with such antiquated units. There is also no good reason why they are converting it for official reasons and to claim that is what people are use to is a self-fulfilling prophecy. Where people ultimately don’t get use it because it gets put into antiquated units. A similar thing can be said about the British press as well as things such as weight loss companies.

    The Daily Mail even has an Australian website where everything is in kg but they stupidity put it into those ye olde rock units because British people are apparently too stubborn and arrogant to get use to weighing themselves in modern, sensible units that are already widely used elsewhere.

    Liked by 1 person

  10. 1.REPLIES FROM THE ROYAL HOUSEHOLD – simply said my comments were noted.
    No reasons, no other information was provided.
    (In the correspondence I stressed the use of metric units in the Commonwealth etc.)

    2.FOR LEE KELLY – please tell us all what physical quantity the ‘fictitious’ unit ‘Kelvin gram’ is used for.


  11. “There is also no good reason why they are converting it for official reasons and to claim that is what people are used to is a self-fulfilling prophecy.”

    That is precisely what I wrote myself. The more people are “fed” the old units, the less they are likely to relate to their weight in kg. Does the NHS actually have a legal duty to provide information in outdated measurements to patients? I understand that it is not its job to familiarise them with metric. That job should have been done by government, and indeed is in that it is what is taught in school. It would probably make life simpler for both the medical staff and patients if they used the same ‘measurement language’, in the same way as, generally speaking, discussions around health issues are conducted in English, not with the two sides speaking different languages!

    If I can be permitted a light-hearted comment, as it always makes me chuckle to think of it. I remember reading once, years ago, a woman wrote that she could not accept a baby’s weight in kilograms as it reminded her of a joint of meat! Weight is weight, or rather mass is mass, whatever you’re weighing. I don’t need to tell readers here that. But I wish I had had the opportunity to speak to the lady whose comment I read.

    Liked by 1 person

  12. Stones and pounds for body weight have become ingrained in the British psyche through habit and laziness to use metric. Like Lee, I rarely get asked my weight, other than by medical staff. In that situation I always reply in kilograms, and my height in centimetres, and have never encountered any reaction. If anyone were to ask me what my weight was in stones/pounds, I’d simply reply “I’ve no idea!”.

    Liked by 1 person

  13. The answer is in the article. When we go shopping we are bombarded with metric units and few items are indicated in imperial nowadays. It is the same with cooking – recipes in magazines, modern cookery books, etc., are nearly always given in metric only. On the other hand, weighing ourselves is something we do less frequently and we have no guidelines over which system we use. The doctor may weigh us in kilograms but that is something that happens relatively infrequently. Our height has not changed significantly since young adulthood, so that is a number we tend to remember and stick to.
    And when I say “we” I mean “many people” of course. I personally believe in keeping up with the times and encouraging society to move on rather than let it drag me back.

    @metricnow @lee kelly
    If you think that the kelvin gram is bizarre, how about the kelvin gram second? I sometimes see it written on the side of lorries and buses.


  14. To those complaining about me using the wrong symbols for kg, please remember that we are trying to encourage people to adopt metrication, and bullying people because they make mistakes isn’t the best way of getting support is it, sure I made an error, are you going to complain when people are trying to change their behaviour? Because it is the best way of making people not change to metrication.. I thank you for your time.


  15. Lee Kelly – no complaint was intended; I was simply trying to take a humerous view of the situation. I entirely agree – we should be thankful for those that are promoting the metric system and not be to concerned about any minor errors they may make over the expression of the units. I have made a few mistakes myself in odd places, but I am with you and UKMA in promoting your aims.


  16. I agree with @Metricmac. However if you are driving in Ireland or Australia and get a speeding ticket that has “kph” rather than “km/h”, then this discussion might be useful in substantiating a demand the charge be dismissed on grounds that “kilopicahours” is a meaningless concept.


  17. Just saw a farmer. being interviewed by Arlene Foster on GB News as to why food prices have skyrocketed. He pointed out that Brexit has created all kinds of obstacles to harvesting (missing workforce) and exporting (too much paperwork and regulations) food so farmers are producing less to avoid waste and the missing food has to be imported at higher prices especially now that the UK is a third country vis-a-vis the EU.

    What struck me was that the farmer kept referring to the number of pounds of harvest per acre being down compared to before Brexit. Can someone explain why after all these years folks like this farmer are still using “pounds” and “acres”? I thought “acres” are officially obsolete in the UK and that the weight of goods was routinely given in “kilograms” these days.

    What am I missing here? Thanks!


  18. @Ezra: I think that the farmer was “dumbing things down” for the general public. I did a quick check on the internet and the article at https://www.fwi.co.uk/arable/wheat/harvest-2022-hampshire-wheat-shows-high-yield-despite-low-protein is entirely metric. A few ytears ago, my wife and I were guests of a wheat farmer. He told me what he was doing and everything was in metric units. (I suspect that before we left the EU, farming subsidies were also gven in metric units).

    Given that the yield of wheat is typically 5 tonnes per hectare, the farmer should be giving a figure of 4480 pounds per acre (why not 2 tons per acre?). Of course, he might have been taking a few liberties and just adding three 0’s to his official yield and alling it pounds per acre.


  19. Ezra & Martin,

    I can think of two reasons why this particular farmer used imperial in the interview:

    1.) He was told to by the person conducting the interview. The fake news media often preps interviewees before they go on the air to make sure they don’t say the wrong thing. They may insist that their viewing audience does not speak metric and imperial must be used in the communication of data.

    2.) He has a personal preference for imperial and even if data is presented in metric in official documents, those with a preference for imperial will find a way to get the numbers converted and memorised.

    The choice of pounds over tons is used to make the amount seem larger than what they really are in the same manner that kilogram pricing seems more expensive than pound pricing.


  20. @Martin and @Daniel
    Many thanks for your thoughts, all quite plausible.
    A real shame some folks have not realized SI is the sane way to go and to have dumped Imperial ages ago.

    So, the work of UKMA continues. As it should.
    Best advice I suppose is “Keep calm and carry on.”


  21. @ Ezra Steinberg 2023-05-22 at 19:46

    Because it is on “on GB News”, a channel that I have deliberately removed from my TV system along with, and classified with, RT (Russia Today), just to be certain I do not accidentally fall on those channels.
    It is an awful UK government propaganda channel and Daniels comment 1) above fits perfectly on this occasion.
    Other opinions may vary.


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