Check your body mass index
Body Mass Index (BMI) is a quick screening number that relates your weight to your height. Enter your measurements in either metric or imperial units and this calculator returns your BMI along with the weight category it falls into. It runs entirely in your browser, so your measurements are never uploaded.
The BMI formula
For example, someone 1.75 m tall weighing 70 kg has a BMI of 70 ÷ (1.75 × 1.75) ≈ 22.9 — within the healthy range.
Adult BMI categories
- Under 18.5 — underweight
- 18.5 – 24.9 — healthy weight
- 25 – 29.9 — overweight
- 30 and above — obese
BMI is a general screening tool, not a medical diagnosis. It doesn't distinguish muscle from fat and isn't intended for children, athletes or during pregnancy. Speak with a healthcare professional for advice about your individual health.
Frequently asked questions
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 weight categories?
For adults: below 18.5 is underweight, 18.5 to 24.9 is a healthy weight, 25 to 29.9 is overweight, and 30 or above is obese.
Is BMI accurate for everyone?
BMI is a useful general screening tool but not a diagnosis. It does not distinguish muscle from fat, so very muscular people can read high, and it is not intended for children, pregnancy or athletes. Consult a healthcare professional for personal advice.