How do you know when a child is under/over weight?

[LynetteScavo]

DD is on the 75th centile for height, and the 25th for weight. Obviously she is skinny, but is there a magic formula to know when she is too skinny?

Seriously, no one on MN knows?

TBH, I think children vary so much those charts aren't of any real use unless there is a health problem.
My DD has never had one that is useful. She was born in Oman and had one of theirs. She was, according to the student doctor who was at her delivery, too long and too thin. Not much I could do about it.
She has continued to be too thin, but that is compared to children of differing races.
If you are concerned, I'd have a word with my HV or GP.

All my DC are thin...both boys at this age would say "I don't want to be fat."
I didn't blink. But DD saying it makes me uncomfortable.

DH thinks it's great she's thin, as almost his entire family (inc uncles, aunts, cousins) are obese. My family tend to be spaghetti children but fill a bit later in life.

For the first time ever today we made her finish what she'd been given at a meal. It was only a bowl of vegetable soup, but usually she would only eat half a bowl and give up, but today we told her to eat up. Normally we're very relaxed, and take the approach DC will eat if they are hungry. The thing is she never is hungry.

She will snack on vast amounts of fruit though.

She seems healthy enough, but when it comes to buying summer clothes they will look like they are hanging off her.

www.nhs.uk/tools/pages/healthyweightcalculator.aspx?WT.mc_id=101007 - this can give an indication of whether your lo's are a healthy weight for their height

That's brilliant - thank you. She is just within a healthy weight (8th centile) so I can relax for now.