BMI Calculator
Work out your Body Mass Index in seconds. Switch between metric and imperial, enter your height and weight, and see your BMI, the category it falls in, and the healthy-weight range for your height. Updates as you type. Runs in your browser; no signup.
BMI categories (adults)
- Under 18.5 — underweight
- 18.5 – 24.9 — healthy weight
- 25.0 – 29.9 — overweight
- 30.0 and above — obese
BMI is a quick screening number, not a diagnosis. It doesn't account for muscle mass, body composition, age, or sex, so very muscular people can read as "overweight" while the number misses other health factors. This tool is for general information only and is not medical advice — talk to a healthcare professional about your individual health.
FAQ
How is BMI calculated?
BMI is your weight in kilograms divided by your height in metres squared (kg/m²). This calculator does the conversion for you whether you enter metric or imperial units.
What is a healthy BMI range?
For adults, under 18.5 is underweight, 18.5–24.9 is a healthy weight, 25–29.9 is overweight, and 30 or above is obese. The calculator also shows the weight range that would put you in the healthy band for your height.
Is BMI accurate for everyone?
No. BMI is a quick screening number, not a diagnosis. It does not account for muscle mass, body composition, age or sex, so very muscular people can read as overweight while it misses other health factors. Use it as a rough guide only.
Does BMI work for children?
Not with these adult categories. Children and teens are assessed with age- and sex-specific BMI percentiles, so use a paediatric tool or ask a healthcare professional for under-18s.
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