Body Mass Index
Calculate BMI from height and weight.
About the Body Mass Index
BMI is a rough screening number, not a diagnosis. It compares weight to height and says nothing about muscle, bone or where fat sits.
How to use it
- Enter your height.
- Enter your weight.
- Read the category alongside the number.
Worked example
Someone 5ft 9in and 170 lb has a BMI near 25.1, just over the line into the overweight band.
Common questions
- What is a healthy BMI?
- Roughly 18.5 to 24.9 for adults, though the bands are population averages, not personal targets.
- Why is BMI criticised?
- It cannot tell muscle from fat. Athletes routinely score overweight or obese while being very healthy.
- Does it work for children?
- No. Children use age and sex-specific percentiles instead.