BMI Calculator
Calculate Body Mass Index (BMI) for adults from height and weight. BMI is a simple screening number, not a diagnosis.
All calculations run in your browser. The numbers you enter are not sent or stored anywhere. Privacy policy
How to use the BMI Calculator
- 1Choose metric (cm, kg) or imperial (feet, inches, pounds).
- 2Enter height and weight.
- 3Read your BMI, its WHO category and the healthy weight range for your height.
Supported formats and limits
- For adults aged 18 and over.
- Not suitable for children, teenagers, pregnant women or very muscular people.
Formula and categories
BMI = weight in kilograms ÷ (height in metres)². The World Health Organization classifies adult BMI as: below 18.5 underweight, 18.5–24.9 healthy weight, 25–29.9 overweight, 30 or above obesity.
Health risks begin at lower BMI levels for many South Asian people, and Indian clinical guidelines use lower cut-offs (overweight from 23, obesity from 25). Talk to a doctor about what is right for you.
This calculator is for general information only and is not medical advice. BMI does not measure body fat directly or account for muscle mass, age or sex.
Frequently asked questions
Is BMI accurate?
BMI is a quick screening tool used across populations. It can overestimate body fat in athletes and underestimate it in older adults. A doctor can assess your health more fully.
Can children use this calculator?
No. Children and teenagers need age- and sex-specific BMI charts.