BMI Calculator
Calculate your body mass index (BMI) based on height and weight, and see which category the result falls into.
How to use the BMI calculator
- Enter your height in centimeters.
- Enter your weight in kilograms. The result updates automatically.
- See which category your BMI value falls into in the explanation below.
How BMI is calculated
BMI (body mass index) is calculated by dividing your weight in kilograms by your height in meters, squared:
BMI = Weight (kg) ÷ Height (m)²
A person who is 175 cm tall and weighs 72 kg gets: 72 ÷ 1.75² = 72 ÷ 3.0625 ≈ 23.5.
What does the BMI number mean?
- Under 18.5 — underweight
- 18.5–24.9 — normal weight
- 25–29.9 — overweight
- 30 and above — obese
Note: BMI doesn't account for muscle mass, body frame, age or sex, and should be seen as a simplified indicator — not a medical diagnosis. Talk to a doctor or healthcare professional for a complete assessment of your health.
Frequently asked questions
Is BMI accurate for everyone?
No. BMI is a simplified calculation that doesn't distinguish between muscle and fat mass. Athletes with a lot of muscle, for example, can get a high BMI without having excess body fat.
Do the same BMI thresholds apply to children?
No, children and teenagers use separate growth charts that account for age and sex. This calculator is intended for adults.