BMI Calculator
Check your Body Mass Index and weight category in metric or imperial.
cm
kg
Enter your height and weight to calculate BMI.
This BMI calculator works out your Body Mass Index from your height and weight and shows which standard category it falls into: underweight, normal, overweight, or obese. You can switch between metric (centimetres and kilograms) and imperial (feet, inches, and pounds) with one tap.
BMI is a quick, widely used screening figure that estimates whether your weight is in a healthy range for your height. The result updates as you type, and everything is calculated in your browser without uploading any personal measurements.
How to use
- Choose metric or imperial units at the top.
- Enter your height — in centimetres, or in feet and inches.
- Enter your weight in kilograms or pounds.
- Read your BMI value and the weight category shown with it.
FAQ
- How is BMI calculated?
- BMI is your weight in kilograms divided by the square of your height in metres. In imperial units it is 703 times your weight in pounds divided by the square of your height in inches.
- What are the BMI categories?
- Under 18.5 is underweight, 18.5 to 24.9 is normal, 25 to 29.9 is overweight, and 30 or above is obese, following the World Health Organization ranges for adults.
- Is BMI accurate for everyone?
- BMI is a general screening tool and does not distinguish muscle from fat, so very muscular people or certain body types may get a misleading reading. Treat it as a rough guide, not a diagnosis.
- Does BMI apply to children?
- Standard adult BMI categories do not apply to children and teenagers, who are assessed with age- and sex-specific percentile charts instead.
- Is my data sent anywhere?
- No. The calculation runs entirely in your browser with JavaScript. Your height and weight are never transmitted, saved, or shared.