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BMI Calculator

Calculate body mass index from weight and height in metric or imperial units, with the WHO category.

Result

Enter your values and select Calculate to see the result.

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How the BMI Calculator works

Choose metric or imperial units, enter your weight and height, and select Calculate BMI. You'll see your body mass index, the World Health Organization category for adults, and the weight range that gives a BMI between 18.5 and 24.9 at your height.

Formula

BMI = kg ÷ m2

Where:

kg
Weight in kilograms
m
Height in metres

Imperial values are converted exactly first (1 lb = 0.45359237 kg, 1 in = 2.54 cm), so both tabs give the same result.

Examples

70 kg, 175 cm

70 ÷ 1.75² = 22.9, a healthy weight. The healthy range at this height is 56.7–76.3 kg.

154 lb, 5 ft 9 in

BMI 22.7.

Frequently asked questions

What are the BMI categories?

For adults the WHO uses: under 18.5 underweight; 18.5 to 24.9 healthy weight; 25 to 29.9 overweight; 30 and above obesity (class I from 30, class II from 35, class III from 40).

Does BMI apply to children?

Not with these categories. For children and teenagers, BMI is compared with age- and sex-specific growth charts.

Information:

Good to know

BMI is a quick screening measure, not a diagnosis. It doesn't distinguish muscle from fat or account for age, sex or ethnicity. Speak to a health professional about your health.

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