BMI Calculator
Your body mass index, the healthy weight for your height and the calories you need a day
Body mass index
Calories a day
Your basal metabolic rate and the calories that keep, lose or gain weight
Type your age, and your height and weight above, to see your calories.
For information only, not medical advice. BMI is a screening measure for adults aged 18 and over, it doesn't tell fat from muscle and doesn't suit children, pregnant women or athletes. Calorie needs are estimates and vary from person to person. Talk to a doctor or a dietitian about your weight and your diet.
How to calculate your BMI
- Choose metric (cm, kg) or US units (ft, in, lb).
- Type your height and weight.
- Read your BMI, its category and the healthy weight range for your height.
- Add your age, sex and how active you are to see the calories you need a day to keep, lose or gain weight.
Questions
What is a healthy BMI?
For adults, the World Health Organization calls 18.5 to 24.9 healthy, 25 to 29.9 overweight and 30 or more obese.
How are the calories worked out?
From your basal metabolic rate with the Mifflin-St Jeor equation, multiplied by how active you are.
Is BMI accurate for everyone?
It's a quick screening number: it doesn't tell muscle from fat, and it reads differently for athletes, older people, children and pregnancy. It isn't medical advice.
Are my details sent anywhere?
No, everything is worked out in your browser.