BMI Calculator
Calculate your Body Mass Index in metric or imperial units.
How to use the bmi calculator
- Choose metric or imperial units.
- Enter your height and weight.
- Your BMI and weight category are calculated instantly.
Calculate your Body Mass Index (BMI) using your height and weight in either metric (cm/kg) or imperial (ft-in/lb) units, and see which standard BMI category your result falls into.
The BMI formula and categories
BMI is your weight in kilograms divided by your height in meters squared. For example, someone who weighs 70 kg and is 1.75 m tall has a BMI of 70 / (1.75 × 1.75) = 22.9. In imperial units the formula is 703 × weight in pounds / height in inches squared.
For adults, the standard categories are: under 18.5 underweight, 18.5 to 24.9 normal weight, 25 to 29.9 overweight, and 30 or above obese. BMI is a quick screening number, not a diagnosis, so talk to a doctor about your own health.
Frequently asked questions
What is a healthy BMI range?
For most adults, a BMI between 18.5 and 24.9 is considered a healthy weight range, according to standard BMI categories. BMI is a general screening tool, not a diagnosis.
Is BMI accurate for everyone?
BMI doesn't distinguish between muscle and fat, so it may be less accurate for athletes, older adults, or pregnant women. Consult a healthcare provider for personalized advice.
Does BMI apply to children?
Not directly. For children and teens, BMI is compared against age- and sex-specific percentile charts, so adult categories don't apply.
Why can athletes have a high BMI?
BMI doesn't separate muscle from fat. Muscular people often score as overweight even with low body fat.