How to calculate your BMI
- Choose metric (kg, cm) or imperial (lb, ft, in) units.
- Enter your height and weight.
- Read your BMI, its category and the healthy weight range for your height.
What BMI tells you
BMI compares weight with height to screen for underweight and overweight. It is quick and useful for populations, but not a diagnosis for an individual.
Limitations
BMI does not distinguish muscle from fat or show where fat is stored. Waist circumference and body fat percentage give a fuller picture.
Healthy weight range
The calculator shows the weight range that gives a normal BMI for your height, so you can see how far you are from it in kilograms or pounds.
Frequently asked questions
How is BMI calculated?
BMI is your weight in kilograms divided by your height in meters squared. For example, 70 kg at 1.75 m gives 70 ÷ 1.75² = 22.9.
What is a healthy BMI?
For adults, the WHO classes a BMI of 18.5 to 24.9 as normal weight, 25 to 29.9 as overweight and 30 or more as obese.
Is BMI accurate for athletes?
Not always. BMI does not separate muscle from fat, so muscular people can show as overweight. Body fat percentage is a better measure for them.
Can children use this BMI calculator?
No. Children and teens are assessed with age- and sex-specific BMI percentiles, not the adult categories used here.