BMI
Calculator.
Enter your height and weight in metric or imperial units to get your Body Mass Index, the matching WHO category, and the healthy weight range for your height.
What is BMI?
Body Mass Index (BMI) is a simple measure of body fatness based on weight and height. It's used as a screening tool and not a diagnostic — muscle mass, frame size and body composition affect interpretation.
Formula
Metric: BMI = weight (kg) / height (m)² Imperial: BMI = 703 × weight (lb) / height (in)²
WHO categories
Underweight: BMI < 18.5 Normal: 18.5 ≤ BMI < 25 Overweight: 25 ≤ BMI < 30 Obese: BMI ≥ 30
Frequently asked questions
What does BMI Calculator do?
BMI with imperial and metric units, plus risk bands. The whole thing runs in your browser tab, so it is ready the moment the page finishes loading.
Is BMI Calculator free to use?
Yes. BMI Calculator is completely free on ToolMunch — no trial, no premium tier holding back the main feature, and no daily or hourly cap on how many times you can use it.
Do I need to create an account or sign up?
No. There is no account, no email address, and no login. Open BMI Calculator, do the job, and take the result — nothing is gated behind a signup form.
Are the numbers I enter sent to a server?
No. BMI Calculator runs entirely inside your browser tab, so what you type never leaves your own device. Nothing is uploaded, which means there is no copy of it on a server to worry about.
Does BMI Calculator work on Mac, Windows, and phones?
Yes. BMI Calculator runs in any modern web browser on Windows, macOS, Linux, Chromebook, Android, and iOS. There is nothing to download or install.
Can I use it as many times as I want?
Yes. There is no queue, no per-hour quota, and no counter that runs out — run BMI Calculator as often as the work needs.