BMI Calculator
Calculate your Body Mass Index in metric or imperial units: WHO weight categories and the healthy weight range for your height. Instant and private.
Why check your BMI
Body Mass Index is the quickest screening check of whether your weight is in a healthy range for your height. Doctors and WHO use it as the first indicator — one division, instantly interpreted. This calculator does the math and shows where you stand on the WHO scale, plus the weight range considered healthy for you.
What it does
- BMI from metric (kg/cm) or imperial (lb/ft) inputs.
- WHO categories: underweight, normal, overweight, obesity classes I–III.
- The healthy weight range for your height in your preferred units.
How to use
- Choose metric or imperial units.
- Enter your height and weight.
- Read your BMI, its category and your healthy weight range.
How it works
BMI equals weight in kilograms divided by the square of height in meters. The categories follow WHO cut-off points: below 18.5, 18.5–24.9, 25–29.9, 30–34.9, 35–39.9, 40+. The calculation runs entirely in your browser.
Frequently asked questions
Is BMI accurate for everyone?
It is a population-level screening tool. It does not distinguish muscle from fat, so athletes may read "overweight" while being healthy. Use it as a first check, not a diagnosis.
What BMI is healthy?
WHO considers 18.5–24.9 the normal range for adults. The calculator also shows the exact weight range that keeps you inside it for your height.