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Original poster

Is there anyone here who could correctly calculate my child’s height/weight centile please?

11 replies

Limone81 · 13/07/2025 18:03

I have looked on the NHS BMI calculator and I’m worried that he’s close to being underweight.

Ive looked on a height m/weight chart and getting a completely different answer. May be calculating it incorrectly.

Are there any health visitors/medical professionals.

He’s 4 feet 8 height. 4 stone 10 weight.

10 years old.

OP posts:
Chewbecca · 13/07/2025 18:06

NHS child BMI calculator says healthy weight range

Is there anyone here who could correctly calculate my child’s height/weight centile please?
Brokenforsummer · 13/07/2025 18:07

The NHS says he is on the 14th centile and is a healthy weight. What centile was he born on? Has be lost any weight? Any changes in his eating?

Edited because I entered the wrong weight the first time.

Original poster
Limone81 · 13/07/2025 18:11

https://www.rcpch.ac.uk/sites/default/files/Boys_2-18_years_growth_chart.pdf

Im getting a different answer from this chart. Unless I’m doing it wrong?

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Original poster
Limone81 · 13/07/2025 18:14

Brokenforsummer · 13/07/2025 18:07

The NHS says he is on the 14th centile and is a healthy weight. What centile was he born on? Has be lost any weight? Any changes in his eating?

Edited because I entered the wrong weight the first time.

Edited

He was born on l around the 90th, but he was massive. Really chunky.

He’s always been around the 50th throughout childhood but has dropped to quite low.

No dramatic change his his eating but he’s very very active so might need to increase his calories.

I just want to make sure I’m getting the correct answer

OP posts:
Jennyathemall · 13/07/2025 18:15

he about 30kg so he’s on about the 40th percentile for weight which is fine. But he on
something like the 70th for height so he probably looks tall and thin.

Original poster
Limone81 · 13/07/2025 18:19

Jennyathemall · 13/07/2025 18:15

he about 30kg so he’s on about the 40th percentile for weight which is fine. But he on
something like the 70th for height so he probably looks tall and thin.

Thank you, that’s what I’m getting too from the chart.

But the NHS calculator is putting him on around 14th centile. No idea why.

He doesn’t look too thin, just a normal wiry boy,

OP posts:
DongDingBell · 13/07/2025 18:22

OK, so the NHS looks at height and weight and age, and gives you one number.

The charts you linked to do height and age, and weight and age is separate. You also need to take into account if they are, say, and average height, but low weight centile, that is less average than a similar centile for both.

If you stick with the NHS, and go with the 14th centile others have calculated, it could be healthy for him - my oldest sits between 9th and 15th usually. What is more concerning is if - as you've mentioned - he has started off on high centiles, and keeps dropping. That is worth keeping an eye on.

Original poster
Limone81 · 13/07/2025 18:37

DongDingBell · 13/07/2025 18:22

OK, so the NHS looks at height and weight and age, and gives you one number.

The charts you linked to do height and age, and weight and age is separate. You also need to take into account if they are, say, and average height, but low weight centile, that is less average than a similar centile for both.

If you stick with the NHS, and go with the 14th centile others have calculated, it could be healthy for him - my oldest sits between 9th and 15th usually. What is more concerning is if - as you've mentioned - he has started off on high centiles, and keeps dropping. That is worth keeping an eye on.

Thanks, I’ve just checked in his red book and I’m getting the same answer as the charts. It’s around 75th for height and 45th for weight.

Does the NHS bmi calculator work differently? I’m confused.

Usually he comes up around 50th centile on BMI calculator. Although it’s not like I’m weighing him all the time. Probably once a year.

He has become much more active the past year or so, so I’m going to try to increase his calories anyway.

I’ll keep an eye on it. I was quite alarmed when I realised he’d dropped on the centiles.

OP posts:
Original poster
Limone81 · 13/07/2025 18:41

DongDingBell · 13/07/2025 18:22

OK, so the NHS looks at height and weight and age, and gives you one number.

The charts you linked to do height and age, and weight and age is separate. You also need to take into account if they are, say, and average height, but low weight centile, that is less average than a similar centile for both.

If you stick with the NHS, and go with the 14th centile others have calculated, it could be healthy for him - my oldest sits between 9th and 15th usually. What is more concerning is if - as you've mentioned - he has started off on high centiles, and keeps dropping. That is worth keeping an eye on.

Ok I think I get it now.

If I’m correct, NHS bmi calculator looks at the overall picture rather than height/weight individually.

Thank you.

OP posts:
Chewbecca · 13/07/2025 18:42

He may just be having a growth spurt? He’s still healthy.

Original poster
Limone81 · 13/07/2025 18:44

Chewbecca · 13/07/2025 18:42

He may just be having a growth spurt? He’s still healthy.

Yes maybe.

Both my dc have always been right in the middle of the BMI so I was a bit alarmed to see he’d dropped to 14th.

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