Find your Body Mass Index from your height and weight, see which World Health Organization category it falls into and the healthy weight range for your height. Works in kilograms/centimetres or pounds/feet.
How to use the BMI Calculator
- Choose metric (kg, cm) or imperial (lb, ft/in) units.
- Enter your height and weight.
- See your BMI, category and healthy weight range instantly.
BMI formula
BMI = weight (kg) ÷ height (m)². In imperial units, BMI = 703 × weight (lb) ÷ height (in)².
BMI categories (adults)
Under 18.5 — underweight. 18.5–24.9 — healthy weight. 25–29.9 — overweight. 30 and above — obesity (class I 30–34.9, class II 35–39.9, class III 40+).
Limitations of BMI
BMI does not distinguish muscle from fat, so athletes may score as overweight. It is a screening tool for adults, not a diagnosis. Children and teens need age- and sex-specific percentiles. Speak to a health professional for personal advice.
Frequently asked questions
What is a healthy BMI?
For most adults a BMI between 18.5 and 24.9 is considered healthy.
Is BMI accurate for muscular people?
Not always. Muscle is dense, so muscular people can have a high BMI with low body fat.
Can children use this calculator?
No. BMI for under-20s must be compared to growth charts by age and sex.