To calculate BMI, enter your weight and height into the BMI Calculator; it divides your weight in kilograms by your height in metres squared and shows the WHO adult category. BMI is a screening measure and not a diagnosis.
How to use the BMI Calculator
- Enter your weight and height in your preferred units.
- Read your BMI and its category.
- Read the notes on its limitations.
- Discuss any concerns with a health professional.
Worked example
A person weighing 70 kg at 1.75 m has a BMI of 70 divided by 3.0625, which is about 22.9, in the WHO healthy-weight range of 18.5 to 24.9.
Tips and common mistakes
- BMI does not distinguish muscle from fat, so athletes can score high.
- It does not account for age, sex or where fat is stored.
- Use it as one indicator alongside other measures, not as a verdict.
Frequently asked questions
What are the WHO BMI categories?
Under 18.5 is underweight, 18.5 to 24.9 is healthy, 25 to 29.9 is overweight and 30 or more is obese, for adults.
Is BMI accurate?
It is a rough screening tool with well-known limitations.
Is this medical advice?
No. Talk to a healthcare professional about your health.