Use this free BMI calculator to find your Body Mass Index in seconds. BMI is a quick screening number that estimates whether your weight sits in a healthy range for your height.
BMI divides your weight in kilograms by the square of your height in metres: BMI = weight (kg) ÷ height (m)². For example, someone who weighs 70 kg and is 1.75 m tall has a BMI of 70 ÷ (1.75 × 1.75) = 22.9. If you use pounds and inches, the formula is weight (lb) ÷ height (in)² × 703.
The World Health Organization groups adult BMI into these ranges:
| BMI range | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obese |
BMI is a useful starting point but it does not measure body fat directly. It does not account for muscle mass, bone density, age, sex, or where fat is stored, so a very muscular person can score high without being overweight. These adult ranges also do not apply to children, teenagers, or pregnant people. Treat your number as one signal among many.
BMI is accurate as a quick screening tool but is not a diagnosis. It can misclassify very muscular or very lean people because it cannot tell muscle from fat.
For most adults a BMI between 18.5 and 24.9 is considered healthy, though the ideal figure varies with age, ethnicity, and body composition.
The adult BMI ranges are the same for both. However, at the same BMI women tend to carry more body fat than men.
No. The calculation runs entirely in your browser and nothing you type is sent to a server or stored.
This calculator is for general information only and is not medical advice. Talk to a qualified healthcare professional about your individual health.