Body mass index compares weight with height. Enter yours in metric or US units to see your BMI, its category and the weight range considered healthy for your height.
BMI calculator
Your BMI
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This calculator gives a general estimate for adults and is not medical advice. Talk to a doctor or a registered dietitian before making health decisions.
How it works
BMI = weight (kg) ÷ height (m)²
In US units: 703 × weight (lb) ÷ height (in)²
Below 18.5 — underweight
18.5 to 24.9 — healthy weight
25 to 29.9 — overweight
30 or more — obesity
BMI is a quick screening number, not a diagnosis. It does not tell muscle from fat, so athletes can score as overweight, and it reads differently for older adults and some ethnic groups — several Asian health bodies use 23 and 27.5 as cut-offs. For children and teenagers, BMI is judged against age- and sex-specific growth charts, so this calculator is for adults only.
Common questions
Is BMI accurate?
It is a good population-level indicator but can mislead for individuals. Waist size and body fat percentage add useful detail.
What is a healthy BMI?
For most adults, 18.5 to 24.9. The calculator shows the weight range this means for your height.