Guides ·
How to use BMI Calculator
BMI Calculator. Body mass index with WHO categories. 18.5 to 24.9 for adults. 25–29.9 is overweight and 30 or more is obesity (WHO).
The short answer
To calculate BMI, divide weight in kilograms by height in metres squared: 70 kg at 1.75 m is 70 ÷ 1.75² = 22.9, a healthy weight. Enter metric or US units to see your BMI, WHO category, BMI Prime and the healthy weight range for your height.
It runs in your browser. What you enter is not uploaded.
How to use it
Enter your values in the fields; defaults show a worked example.
Pick the units or options that apply to you.
Read the result, which updates instantly as you type.
Check the formula note under the result to see exactly how it was worked out.
Limits worth knowing
What is a healthy BMI? 18.5 to 24.9 for adults. 25–29.9 is overweight and 30 or more is obesity (WHO). For many Asian populations, the WHO suggests action from 23.
Is BMI accurate for athletes? Not always. BMI cannot tell muscle from fat, so muscular people can be 'overweight' by BMI while lean. Waist size or body fat % adds context.