Free BMI Calculator
Calculate your Body Mass Index (BMI) in metric or imperial units and see your weight category.
Enter your height and weight to calculate BMI.
How to calculate your BMI
- Choose metric or imperial units.
- Enter your height and weight.
- See your BMI and weight category instantly.
How BMI is calculated
BMI is calculated as weight in kilograms divided by height in meters squared. This calculator uses that same standard formula regardless of which unit system you enter your measurements in.
A note on scope
BMI is a simple screening measure based only on height and weight — it does not account for muscle mass, body composition, age, sex, or ethnicity, and is not a diagnosis. Talk to a healthcare provider for a fuller picture of your health.
Common use cases
- Check your BMI using metric measurements
- Check your BMI using imperial measurements
- See which BMI category your result falls into
Frequently asked questions
Is this BMI calculator free?
Yes. It is completely free, with no signup and no limits.
Are my measurements uploaded anywhere?
No. The calculation happens locally in your browser.
What are the BMI categories?
Underweight (below 18.5), Normal weight (18.5-24.9), Overweight (25-29.9), and Obese (30 and above), using the standard adult BMI ranges.
Is BMI accurate for everyone?
No. BMI doesn't distinguish muscle from fat, so it can be less accurate for athletes, older adults, and some other groups. It's a general screening tool, not a diagnosis.
Can I use pounds and feet/inches instead of kg and cm?
Yes. Switch to imperial units to enter height in feet and inches and weight in pounds.