Free BMI Calculator Online: Body Mass Index & WHO Range
Calculate your Body Mass Index from your height and weight, and see your WHO range: underweight, normal, overweight or obesity.
Calculate your Body Mass Index (BMI) from weight and height and check the WHO classification: underweight, normal, overweight or obese. For informational purposes only.
By VOV · Last updated: October 21, 2026
BMI is a guidance indicator: it does not distinguish muscle from fat and ignores age or build. It is not a medical diagnosis — consult a health professional.
Use cases
- Calculate your body mass index to check if you're in a healthy range before starting a diet
- Check your teenage child's BMI and compare the result against the WHO's official reference tables
- Use your BMI as a starting point before booking an appointment with a personal nutritionist
Frequently asked questions
How is BMI calculated?
Weight in kilograms divided by height in meters squared. Example: 70 kg and 1.75 m → 70 ÷ (1.75 × 1.75) = 22.9.
What are the WHO BMI ranges?
Below 18.5: underweight; 18.5–24.9: normal; 25–29.9: overweight; 30 or above: obesity.
Does BMI work for athletes?
With caveats: muscle weighs more than fat, so a very muscular person can score "overweight" while being fit. It is a population guide, not an individual diagnosis.