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.
Two examples
| Weight | Height | BMI | Category | Healthy range |
|---|---|---|---|---|
| 70 kg | 175 cm | 22.9 | healthy weight | 56.7 to 76.6 kg |
| 95 kg | 180 cm | 29.3 | overweight | 59.9 to 81.0 kg |
At 95 kg and 1.80 m the calculator shows that 14.0 kg less would bring you to the top of the healthy range. It is a reference point, not a target. Weight loss goals are best set with a doctor. To convert your weight or height from pounds and feet, use the kg to pounds converter and the metres to feet converter.
Other cut-offs
The categories above are the WHO's for adults. Some guidelines use lower cut-offs for people of Asian descent, with health risks rising from a BMI of about 23. The waist circumference is a useful second measurement, since fat around the belly carries more risk than fat on the hips.
Units
You can enter the height in centimetres or in metres, such as 1.80. The calculation is always weight in kilograms divided by the height in metres squared.
Frequently asked questions
How do I calculate BMI in pounds and inches?
BMI = 703 × weight in pounds ÷ (height in inches)². For 154 lb and 5 ft 9 in (69 in): 703 × 154 ÷ 4,761 ≈ 22.7. Or convert with the [kg to pounds](/en/math/kg-to-pounds-converter) and [metres to feet](/en/math/meters-to-feet-converter) converters first.
Is BMI accurate for athletes?
Not always. Muscle weighs more than fat, so a muscular person can have a BMI in the overweight range at a healthy body fat level. BMI does not measure body fat or where it is stored.
What is the healthy weight range shown?
The weights at your height that give a BMI from 18.5 to 25. At 175 cm that is 56.7 to 76.6 kg. If your weight is outside, the calculator also shows how many kilos away you are.
Can I use it for children?
No. For under 18s the categories depend on age and sex, and growth charts are used instead. If you have questions about a child's weight, talk to a doctor.