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BMI Calculator: body mass index for adults, with context

Enter your height and weight to see your body mass index and the adult category it falls in, with the context BMI leaves out.

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BMI is a screening number for adults, not a diagnosis. It does not measure body fat directly; talk to a health professional about your own health. Prime Adapt keeps your personal health data private and under your control.

Questions people ask

What is BMI?

Body mass index is weight in kilograms divided by height in metres squared. For adults, the World Health Organization uses 18.5–24.9 as the healthy range.

Is BMI accurate for people who lift?

Not always. BMI can't tell muscle from fat, so muscular people can read as overweight. It also varies with age and ethnicity; some guidelines use lower thresholds for people of Asian heritage.

What adds more context?

Waist-to-height ratio shows fat carried around the middle. NICE guidance (2022) suggests keeping your waist below half your height.

Does it apply to children?

No. Children and teenagers need age- and sex-specific growth charts.