BMI Calculator
Work out your Body Mass Index from your height and weight.
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BMI
About this tool
Body Mass Index (BMI) is a quick way to gauge whether your weight is in a healthy range for your height. Enter your weight in kilograms and your height in centimetres and this calculator shows your BMI along with the category it falls into.
BMI is a general guide rather than a diagnosis — it doesn't account for muscle mass, build or age — but it's a widely used starting point. The calculation runs entirely in your browser; nothing you enter is uploaded.
Frequently asked questions
- How is BMI calculated?
- BMI is your weight in kilograms divided by the square of your height in metres (kg/m²). For example, 70 kg and 1.75 m gives a BMI of about 22.9.
- What do the categories mean?
- Under 18.5 is underweight, 18.5 to 24.9 is a normal weight, 25 to 29.9 is overweight, and 30 or above is in the obese range.
- Is BMI accurate for everyone?
- It's a rough guide. Very muscular people can read as overweight, and it's not suitable for children or during pregnancy. Treat it as one signal, not a verdict.