BMI Calculator
Calculate your body mass index from your height and weight in kg/cm or lb/ft. See your BMI category and the healthy weight range for your height. Free.
- Healthy weight for your height
- 56.7 kg – 76.3 kg
- BMI Prime
- 0.98
An estimate from a published formula, for general information. It isn't medical advice; talk to a doctor or dietitian about your own needs.
What your BMI means
Body mass index is your weight in kilograms divided by your height in metres squared. The World Health Organization groups adult BMI into four bands: under 18.5 is underweight, 18.5 to 24.9 is a healthy weight, 25 to 29.9 is overweight and 30 or more is obese. BMI is a quick screening number, not a diagnosis: it doesn't separate muscle from fat, so very muscular people can score 'overweight' while being lean, and it reads differently for older adults and some ethnic groups. For children and teens, doctors use age- and sex-specific BMI percentiles instead.
How to use it
- 1
Pick your units
Use kilograms and centimetres, or pounds, feet and inches.
- 2
Enter height and weight
Weigh yourself without shoes or heavy clothes for the best result.
- 3
Read your BMI
See your BMI, its category and the weight range that counts as healthy for your height.
Frequently asked questions
How is BMI calculated?
BMI = weight (kg) ÷ height (m)². For 70 kg and 1.75 m: 70 ÷ (1.75 × 1.75) = 22.9. In US units it's 703 × weight (lb) ÷ height (in)².
What is a healthy BMI?
18.5 to 24.9 for most adults. Some health bodies use a lower threshold of 23 for overweight in people of South Asian, Chinese and other Asian backgrounds, because health risks rise at a lower BMI.
Is BMI accurate for athletes?
Not very. Muscle is denser than fat, so BMI overestimates body fat in muscular people. A body fat or waist measurement tells you more.
Can I use this for my child?
No. Children's BMI has to be compared with growth charts for their age and sex. Ask your doctor or use a child BMI percentile calculator.