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BMI calculator
Body mass index (BMI) relates your weight to your height: weight in kilograms divided by height in metres squared. The World Health Organization uses it to classify weight in adults.
It's only a guide: it doesn't tell muscle from fat. A very muscular person can have a high BMI without excess fat, so look at it alongside your waist measurement and how you feel.
Frequently asked questions
What is a normal BMI?
According to the WHO, 18.5 to 24.9 is considered a normal weight for adults.
Is BMI useful for athletes?
Only partly: since it doesn't tell muscle from fat, it can overestimate excess weight in muscular people.
Can it be used for under-18s?
No. Children and teenagers use percentile charts by age and sex.
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