BMI Calculator
Calculate your Body Mass Index from height and weight — in kilograms and centimetres or in pounds, feet and inches. The scale shows where you fall within the WHO categories, and below you'll find what the number does and doesn't tell you.
Calculate your BMI
Enter your weight and height to see your BMI.
Where you fall on the WHO scale
Good to know about BMI
What is the Body Mass Index?
The Body Mass Index estimates whether a person's weight fits their height by dividing body weight by the square of body height: BMI = kg ÷ m². The World Health Organization uses it as a simple screening index for adults of all ages and both sexes, with the normal-weight range set at 18.5 to 24.9. Because it needs only two everyday measurements, it is the most widely used weight classification worldwide.
WHO classification for adults
What BMI cannot tell you
BMI does not distinguish muscle from fat: athletic people can score as overweight while carrying little fat, and older people can score as normal weight while having lost muscle. Body composition, waist circumference and where fat is stored matter at least as much as weight alone.
The adult categories do not apply to children and teenagers — they use age- and sex-specific percentile curves — or during pregnancy. BMI is a statistical screening value, not a medical diagnosis: if your result worries you, discuss it with a doctor.