BMI Calculator
Calculate your Body Mass Index in metric or US units, see which weight category you fall into, and find the healthy weight range for your height.
BMI is a screening number for adults 20+. It does not measure body fat directly — talk to a doctor for health advice.
How to calculate BMI
- Choose metric (cm and kg) or US units (feet, inches and pounds).
- Enter your height and weight.
- Your BMI, category and healthy weight range update instantly.
Formula: BMI = weight in kg ÷ (height in metres)². For US units the calculator converts pounds and inches to metric first, so both give the same result.
Adult BMI categories (WHO): under 18.5 underweight · 18.5–24.9 healthy · 25–29.9 overweight · 30 and above obese.
Frequently asked questions
Is BMI accurate?
BMI is a quick screening tool, not a diagnosis. Muscular people can have a high BMI without extra fat, and older adults can have a normal BMI with low muscle mass.
Can I use this BMI calculator for children?
No. Children and teens are assessed with age- and sex-specific percentile charts. Ask a paediatrician.
What is a healthy BMI range?
For most adults, a BMI between 18.5 and 24.9 is considered healthy. Some Asian health bodies use lower cut-offs (23 for overweight).