BMI Calculator
Calculate body mass index from your height and weight in US or metric units, and see the standard adult weight category it falls into.
Runs in your browser. Nothing you enter is uploaded.
01How to use the BMI Calculator
- 01Choose US or metric units.
- 02Enter your height and weight.
- 03Read your BMI, its category and the healthy weight range for your height.
02BMI formula
BMI = weight (kg) ÷ height (m)² BMI = 703 × weight (lb) ÷ height (in)² Adult categories (CDC / WHO): below 18.5 Underweight 18.5 – 24.9 Healthy weight 25 – 29.9 Overweight 30 and above Obesity
03Examples
5 ft 9 in and 160 lb gives a BMI of 23.6, in the healthy range.
175 cm and 85 kg gives a BMI of 27.8, in the overweight range.
At 5 ft 4 in, the healthy range is roughly 108–145 lb.
04Frequently asked questions
Is BMI accurate for athletes?
Often not. BMI uses only height and weight, so people with a lot of muscle can be classed as overweight while having low body fat.
Can I use this for children?
No. For people under 20, BMI is compared against age- and sex-specific growth charts. These adult categories do not apply.
Why does my result differ slightly from another site?
Some calculators round height or weight before calculating, or use 703 instead of the exact metric conversion. Differences are usually in the first decimal place.