BMI Calculator
Calculate your Body Mass Index (BMI) in metric or US units, see your weight category and the healthy weight range for your height.
About the BMI Calculator
Body Mass Index (BMI) is a quick screening number that compares your weight with your height. This BMI calculator works for adults in both metric and US units, tells you which category you fall into and shows the healthy weight range for your height.
How to Use the BMI Calculator
- Choose metric or US units.
- Enter your height and weight.
- Press Calculate to see your BMI, category and healthy weight range.
Formula and How It Works
BMI = weight (kg) ÷ height (m)². In US units, BMI = 703 × weight (lb) ÷ height (in)². The WHO categories are: underweight below 18.5, normal 18.5–24.9, overweight 25–29.9 and obese 30 or above.
Frequently Asked Questions
What is a healthy BMI?
For most adults a BMI between 18.5 and 24.9 is considered healthy. Some Asian health bodies use a lower cut-off of 23 for overweight.
Is BMI accurate for athletes?
Not always. BMI does not separate muscle from fat, so muscular people can have a high BMI while being lean. A body fat calculator gives more detail.
Results are estimates for general information and are not medical or veterinary advice. Please speak to a qualified professional about your own situation.