BMI calculator

Work out your body mass index, see which range it falls in and what weight is healthy for your height.

How it works

BMI divides weight (kg) by height (m) squared. The WHO considers a BMI of 18.5 to 24.9 healthy, 25 to 29.9 overweight and 30 or more obese.

It’s a quick measure with limits: it can’t tell muscle from fat, so very muscular people can score high without excess fat. It doesn’t apply to under-18s or during pregnancy.

BMI = weight (kg) / height (m)²

Frequently asked questions

What is the ideal BMI?

For adults, between 18.5 and 24.9. There’s no single “perfect” number inside that range.

Does it work for children?

No. Children use percentile charts by age and sex; ask your paediatrician.

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