BMI Calculator
Enter height and weight to get your BMI, the category it falls in and the healthy weight range for your height.
Enter your height and weightYour BMI appears here.
| Below 18.5 | Underweight |
|---|---|
| 18.5 to 24.9 | Healthy weight |
| 25 to 29.9 | Overweight |
| 30 or above | Obesity |
These are the standard adult categories used by the World Health Organization. BMI is a screening measure, not a diagnosis: it does not account for muscle, age, sex or body build, and it is read differently for children. Talk to a health professional about your own situation.
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- Metric and US units
- Healthy weight range for your height
- Standard WHO adult categories
How to use the BMI Calculator
- Choose metric or US/imperial units.
- Enter your height and weight.
- Read your BMI, category and healthy range.
How BMI is calculated
BMI is weight in kilograms divided by the square of height in metres. Someone 1.70 m tall who weighs 68 kg has a BMI of 68 ÷ (1.7 × 1.7) = 23.5. In US units the formula is weight in pounds × 703 ÷ height in inches squared.
What BMI cannot tell you
BMI does not distinguish muscle from fat, so athletic people can score as overweight. It is interpreted with age- and sex-specific charts for children and teenagers, and some health bodies use lower thresholds for people of certain ethnic backgrounds. Use it as a starting point for a conversation with a health professional, not as a verdict.
Questions about the BMI Calculator
Is BMI accurate for everyone?
No. It is a population screening measure. Muscle mass, age, sex, pregnancy and body build all affect how it should be read.
Is the same scale used for children?
No. For under-18s, BMI is compared with growth charts for the child’s age and sex.