BMI Calculator
Calculate your body mass index (BMI) from height and weight, in metric or imperial units.
This tool is for general information only and is not medical advice. Talk to a qualified healthcare professional before making health decisions.
About the BMI Calculator
Body Mass Index (BMI) is a quick screening number that relates your weight to your height. This calculator works it out instantly and tells you which category the result falls into.
Enter your details in metric (kg and cm) or imperial (lb and ft/in) units. The tool shows your BMI to one decimal place along with the standard ranges for underweight, normal, overweight and obese.
BMI is a general guide and does not distinguish muscle from fat, so athletes and very muscular people may read high. Everything is calculated in your browser.
Key features
- Metric and imperial units
- Instant BMI with category
- Standard WHO ranges shown
- Private, in-browser calculation
How to use
- 1Choose metric or imperial units.
- 2Enter your weight and height.
- 3Read your BMI and its category.
Frequently asked questions
- What is a healthy BMI?
- A BMI between 18.5 and 24.9 is considered the normal, healthy range for most adults. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is obese.
- Is BMI accurate for everyone?
- BMI is a useful general screen but does not measure body fat directly or account for muscle mass, so it can be misleading for athletes, older adults and some ethnic groups.
- Does it work for children?
- This calculator uses adult categories. Children and teenagers use age- and sex-specific BMI percentiles, so consult a paediatric chart for them.