BMI Calculator
Calculate your Body Mass Index in metric or imperial units.
Work out your Body Mass Index in kilograms and centimetres or in pounds and feet, and see which category the figure falls into. Runs entirely in your browser.
How to use it
- Choose metric or imperial units.
- Enter your weight and your height.
- Read your BMI and the band it falls into.
Frequently asked questions
How is BMI calculated?
In metric it is weight in kilograms divided by height in metres squared: 70 kg at 1.75 m gives 70 divided by 3.0625, which is 22.9. In imperial the same result comes from pounds multiplied by 703 and divided by inches squared.
What do the categories mean?
The World Health Organization uses under 18.5 for underweight, 18.5 to 24.9 for normal, 25 to 29.9 for overweight and 30 or more for obesity. They apply to adults, not to children or during pregnancy.
Is BMI reliable?
It is a population screening measure, not a diagnosis. It cannot tell muscle from fat, so athletes often score as overweight. Treat it as a starting point and talk to a doctor.