BMI Calculator
Body Mass Index for metric or imperial units. Free, no sign-up, files stay on your device.
BMI is a rough screening measure for adults (18+). It does not measure body fat directly and does not take into account muscle mass, age, sex, ethnicity or body shape, so it can be misleading for athletes, older adults, during pregnancy and for children and teenagers (who need age-specific charts). Some health bodies use lower cut-offs for people of Asian origin. For advice about your health, talk to a doctor.
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How to calculate your BMI
- Choose metric (centimetres and kilograms) or imperial units (feet, inches, stone and pounds).
- Enter your height and weight — the result updates as you type.
- See your BMI, the WHO category it falls into and the healthy-weight range for your height.
Body Mass Index is your weight in kilograms divided by your height in metres squared. The World Health Organization uses these adult categories: under 18.5 underweight, 18.5–24.9 healthy weight, 25–29.9 overweight and 30 or more obesity. BMI is quick and useful for large groups, but it is only a rough screening measure for individuals — waist size, fitness and medical history matter too. Nothing you enter is sent anywhere; values are only remembered in this browser.