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BMI Calculator

Calculate your body mass index (BMI) and get an instant classification of your weight range.

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BMI (body mass index) is a simple metric that relates body weight to height. It is commonly used as a first indicator to classify underweight, normal weight or overweight.

UnitsMetric units are the international default. Switch to US or UK units for height and weight when your comparison uses them.
kg
Use your current body weight; clothing, time of day and scale can vary slightly.
cm
Use height in centimeters; small measurement differences only slightly affect BMI.
years
BMI remains a rough screening indicator; at higher age the normal range is interpreted more cautiously.
Standard BMI classes apply to adults. Children and teenagers need age- and sex-specific percentiles; at higher age the normal range is interpreted more cautiously.
FAQ

FAQ about BMI Calculator

Is BMI accurate?

It is a useful guideline, but not a precise health assessment.

What is a normal BMI?

The normal range is roughly between 18.5 and 24.9.

Why is muscle mass an issue?

Because muscle weighs more than fat and can increase BMI without indicating overweight.

Does BMI work the same for children?

No. Children and teenagers are usually assessed with age- and sex-specific percentiles.

Does BMI replace medical assessment?

No. BMI is only a rough indicator and should be interpreted professionally if there is uncertainty.