BMI Calculator
Body Mass Index (BMI) is a quick screening measure that estimates body fat using your height and weight. Enter your measurements below to see your BMI and where it falls within the standard WHO weight categories.
How to use
- Choose metric (kg/cm) or imperial (lb/ft+in) units.
- Enter your weight and height.
- Your BMI and weight category appear instantly.
Frequently asked questions
What do the BMI categories mean?
The WHO categories are: below 18.5 = underweight, 18.5–24.9 = normal weight, 25–29.9 = overweight, and 30 or above = obese.
Is BMI accurate for everyone?
No. BMI does not distinguish muscle from fat, so athletes often score "overweight" despite low body fat. It is also less meaningful for children, pregnant women and the elderly. Treat it as a rough screening tool, not a diagnosis.
How is BMI calculated?
BMI = weight (kg) ÷ height (m)². In imperial units: BMI = 703 × weight (lb) ÷ height (in)².