BMI calculator
Height and weight give your BMI, the adult category and the healthy weight range for your height.
- Runs on your device
- No sign-up
- Works offline
For adults only. A screening measure, not a diagnosis. The questions below explain what it leaves out.
How to calculate your BMI
- Pick metric or imperial, then enter your height.
- Enter your weight in kilograms, in pounds, or in stone and pounds.
- Read your BMI, the adult category and the healthy weight range for your height.
Questions
How is BMI calculated?
Divide your weight in kilograms by your height in metres, squared. 75 kg at 1.80 m is 75 ÷ (1.80 × 1.80) = 23.1. In imperial units, multiply the weight in pounds by 703 and divide by the height in inches, squared.
What are the adult BMI categories?
The WHO groups are below 18.5 underweight, 18.5 to 24.9 healthy weight, 25 to 29.9 overweight, and 30 or more obesity.
What does BMI leave out?
It does not separate muscle from fat, so a muscular person can score as overweight. It does not adjust for age or ethnic background, and some populations face risk at lower BMI values. It is a screening measure for adults, not a diagnosis or medical advice.
Does this work for children?
No. For people under 18, BMI is compared with age- and sex-specific percentiles on a growth chart, not with the adult cut-offs used here. A doctor or nurse can read those charts with the child.