How BMI Calculator works

Calculate adult body mass index using metric or imperial height and weight inputs.

The formula

Metric BMI = kilograms ÷ metres². Imperial BMI = 703 × pounds ÷ inches².

A practical example

A height of 180 cm and weight of 81 kg produces a BMI of 25.0.

Important limitations

BMI is a screening measure and does not directly measure body fat, fitness or overall health. It is not a diagnosis.

Frequently asked questions

Which reference range is displayed?

The standard adult reference range of 18.5–24.9 is shown neutrally for context.

Is BMI suitable for everyone?

Its interpretation can be limited for children, pregnancy, older adults and people with high muscle mass.