How to use BMI Calculator
- Choose metric (kg and cm) or imperial (lb, feet and inches).
- Enter your weight and height.
- Read your BMI, the category and your healthy weight range.
About this tool
BMI is your weight in kilograms divided by your height in metres squared. For adults, the World Health Organization groups BMI as: under 18.5 underweight, 18.5 to 24.9 healthy weight, 25 to 29.9 overweight, and 30 or more obesity (class 1 from 30, class 2 from 35, class 3 from 40).
BMI is a quick screening measure. It does not distinguish muscle from fat and does not show where fat is stored, so it can be misleading for athletes, older people, some ethnic groups, pregnant women and children, who use different charts. This tool gives general estimates for healthy adults. It is not a medical diagnosis or medical advice. Speak to a doctor or qualified health professional about your own health.
Privacy: This tool runs in your browser. What you type or choose is not sent to a server by this website.
Common questions
What is a healthy BMI?
For most adults, 18.5 to 24.9.
Is BMI accurate?
It is a rough guide for groups of people and a useful starting point, but it is not a measure of individual health. A doctor can consider other factors such as waist size, blood tests and lifestyle.
Can I use it for children?
No. Children and teenagers are assessed with growth charts for their age and sex.