BMI calculator
Enter your weight in kilograms and your height in centimetres, and see your BMI straight away, which category it falls in and the weight range that gives a healthy BMI at your height. Nothing is stored or sent anywhere.
In kilograms.
In centimetres (1.82 m works too).
Fill in the fields; the answer appears here straight away.
How it's worked out
How it works
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Enter the values
Type the numbers or the formula. Decimals may use a point or a comma. No idea? Click Fill in an example.
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Instant answer
The answer appears as you type, with the most important intermediate values.
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See the working
Under "How it's worked out" you see the steps, handy for checking your own calculation.
How BMI is calculated
BMI = weight in kilograms ÷ (height in metres × height in metres). For someone of 78 kg and 1.82 m: 78 ÷ (1.82 × 1.82) = 78 ÷ 3.31 = 23.5. Height in metres (1.82) works too.
What does your BMI mean?
For adults, the World Health Organization uses these ranges:
| BMI | Category | |---|---| | below 18.5 | underweight | | 18.5 to 25 | healthy weight | | 25 to 30 | overweight | | 30 to 40 | obesity | | 40 or more | severe obesity |
Where BMI falls short
BMI is a rough measure. It ignores muscle mass (muscular athletes quickly count as 'overweight'), build and where fat is stored; fat around the waist is less healthy than fat on the hips. For children and teenagers under 18 there are separate charts by age, so this calculator is not meant for them. If you are worried about your weight, talk to your doctor.
Frequently asked questions
Is the BMI calculator free?
Yes. The BMI calculator is completely free, with no account, sign-up or usage limit.
How accurate is the result?
The tool calculates with your browser's number precision. For important calculations, always double-check what you entered.
Does it work on my phone?
Yes. The tool works in any modern browser on a phone, tablet or computer.