How to use the BMI Calculator
- Choose metric (kg, cm) or imperial (lb, ft/in).
- Enter your weight and height.
- See your BMI, its range, and the healthy weight range for your height.
About this tool
BMI is weight in kilograms divided by height in metres squared. The World Health Organization groups adult BMI as underweight (below 18.5), healthy (18.5–24.9), overweight (25–29.9) and obese (30 or more). It is a quick screening number only — it does not measure body fat directly and does not suit children, pregnant women or very muscular people. For advice about your health, talk to a doctor.
Frequently asked questions
Is BMI accurate?
It is a useful rough guide for most adults, but it cannot tell muscle from fat, so athletes may show a high BMI while being healthy.
Can children use this calculator?
No. Children and teenagers are measured with age- and sex-specific BMI charts, which this calculator does not use.
Are the ranges the same for everyone?
These are the WHO ranges for adults. Some health bodies suggest lower cut-offs for people of South Asian descent, so ask a doctor what applies to you.