What did the royal baby really weigh?

One of the most infuriating practices of the British media is to translate the proper medical data recorded by the hospital (in  kilograms, naturally) into the obsolete units that were once used by our grandparents or great-grandparents.  Thus, our future head of state is described as weighing in at “8lbs 6oz”.  So how much is that, and is it a lot or a little?

The National Health Service is supposed to work entirely in metric units.  This principle was reinforced in an exchange in the House of Lords some years ago, when Baroness Thornton assured her questioner, Lord Walton of Detchant, that in order to prevent possibly catastrophic accidents over wrong dosage, the rules requiring metric-only scales were to be strengthened. See http://www.publications.parliament.uk/pa/ld200910/ldhansrd/text/100225-0001.htm#10022584000562.  (The point is that drugs are prescribed in milligrams and relate to body mass in kilograms.  Any additional conversions from or to imperial units would introduce a source of error and are therefore strictly forbidden).

My own son was born at the Queen Elizabeth Hospital in Birmingham in 1975, and I still have the ticket that was attached to his cot and cross-referenced to his wrist band (obviously to prevent babies being presented to the wrong parents).  This is illustrated below (I have redacted his mother’s name).

It can be seen that his weight was given as 3.92 kg – no mention of pounds or ounces.  That was nearly 40 years ago.  Yet still the British media* dumb down this information and translate it into units that are not used in other walks of life (give or take the odd street market trader).  It is as if there is an unspoken conspiracy of the media to prevent British people from progressing into the 21st century.

So what is the answer to the headline question?

8lbs 6oz can be converted (somewhat laboriously) to approximately 3.8 kg.  We cannot be more precise (a) because an ounce is about 28 g, so rounding to the nearest ounce gives a range of 3.786 to 3.814 g; and (b) the imperial figure is itself a conversion from the original metric data, and converting backwards and forwards and then rounding to the nearest whole number inevitably results in loss of precision (and accuracy).

An average newborn baby weighs about 3.4 kg (though the “normal” range is from 2.5 to 4.6 kg).  So the royal baby (like my son) was above average weight at birth, but well within the “normal” range.


*To be fair, the media got their information from the public relations department of the hospital, who in turn issue the information in lbs and oz (presumably because they think this is what the media want).  I actually telephoned the St Mary’s Hospital press office to ask for the birth weight in kilograms, but the respondent was clueless, suggesting that I could convert from the imperial amount, adding that they were unable to release medical information on individual patients.

[Actually, if the last statement is true, then the information may have come from the Palace PR department, in which case the same strictures apply to them. – Erithacus]

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61 Responses to What did the royal baby really weigh?

  1. Daniel Jackson says:

    The question to Jake is, why would the metric mass of the baby be a medical secret? If they give out a fake imperial weight, why not a also a fake metric mass? Real or fake, why are they hiding the metric value from the public as if it doesn't exist?

  2. Jake says:

    @Daniel Jackson

    I agree with what you say. I wish I had an answer to your question.

  3. BrianAC says:

    No surprise at the latest addition of royal babies mass being posted in non metric units.
    What I find even more disturbing is the way the time is posted, '0526am', what level of education and care of presentation does that reveal? Given that the UK has used the correct international notation on all bus and train time tables since around 1963 I do not see what is so out of place in its use. True the royals probably do not travel by bus, but the employees may well have used one. At least the BBC online gave a metric of 3.2 kg, albeit in brackets without the space, and the correct and intelligible time of 05:26 BST.

  4. Daniel Jackson says:

    Well Brian, do we really know it is 3.2 kg? Unless someone from the hospital leaked the value that appeared on the balance and was entered into the baby's record to the BBC, it could be almost anything. I'm not a fan of imperial to metric conversions especially when the original value was metric to begin with.

  5. Jake says:

    Brian AC:

    The Sydney Morning Herald reported the latest birth this way:

    "Buckingham Palace said the baby weighed 7lb 3oz (an old-fashioned way of saying 3.3kg, or about average)."

    I read '0526 hrs' on the official announcement, by the way. Was it originally put out the way you said and corrected, perhaps?

  6. BrianAC says:

    @ Daniel, Jake,

    We will never know the true weight and really do not need to know, it is their information and not necessarily for public consumption. That does not mean it has to be approximated into some weird units of measure.
    Portable class 3 midwife scales typically resolve to 10 g and fixed scales to 5 g, so rounding to the nearest single digit would give reasonable ambiguity to preserve privacy I would have thought.

    The official time was given as '0526am' (sic) on the gilt easel, that is not the sort of muddle we should be seeing in any official announcement.

  7. Gavin says:

    Actually, the BBC News on first announcing the birth had in a caption going across the screen the weight in kilos only!!. Sadly the presenter announced the weight in imperial, so the beeb deserve a little credit.

  8. Daniel Jackson says:

    Here's why this has tuned into a muddle. Brian stated BBC originally gave the mass as 3.2 kg and Gavin stated in the text the metric mass was the only one given. If the mass was determined by the balance to the nearest 10 g and rounded to the nearest 100g, we can possibly agree the 3.2 kg value to be correct.

    Then somewhere along the way it was converted from 3.2 kg to 7 pounds 0.88 ounces and rounded to 1 ounce. But, the value given is 7 lb - 3 oz, and increase of 2 ounces which back converts to 3260 g and when rounded it is 3.3 kg as was stated in the Australian press.

    In the reporting of a baby's mass to the public, this is a trivial issue but what if this nonsense is done in situations where the numbers are important? Back and forth converting with rounding or other errors factored in and someone could be critically injured or killed.

  9. Daniel Jackson says:

    Essential baby from Australia: 3.35 kg


    Paris News: 7 lb 3 oz (3.2 kg)


    As noted earlier, 3.2 kg is 7 lb 1 oz not 3 oz.

    So, which is the actual correct value in grams as measured by the hospital?

  10. Jake says:

    Brian AC:

    I must correct myself: I saw 0526hrs on some kind of announcement that Google found for me, but it was not the announcement on the easel outside the Palace, which as you say, gave the time of birth in a nonsensical way. Do they not have people in the Palace to check these things? As for the various figures in 'pounzernounces', we simply see how converting back and forth leads to all kinds of rounding up and down and to potential error.

  11. BrianAC says:

    We probably all agree this is a bit of a trivial pursuit, that is until a baby needs serious hospital attention. At that point in time, under stress, pressure and urgency various people doing on-the-fly conversions back and forth, based on doubtful information to start with is when the problems become a bit more serious. Dates, time (of last meal/medication), mass, height all need to be quite unambiguous and understood by all.


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