BMI Calculator
Last updated: June 1, 2026Check your Body Mass Index in seconds.
BMI Calculator is a free online calculator to check your Body Mass Index in seconds. It runs entirely in your browser, so your files never leave your device — nothing is uploaded. There's no sign-up, no watermark, and it works on any modern browser on desktop or mobile.
How to use BMI Calculator
The BMI Calculator works out your Body Mass Index from your height and weight and shows which World Health Organization category you fall into. Switch between metric (cm/kg) and imperial (ft/in, lb). It's free, instant and runs entirely in your browser.
- 1Choose metric or imperial units.
- 2Enter your height and weight.
- 3Read your BMI and category instantly.
Metric & imperial
Calculate in cm/kg or feet, inches and pounds — whichever you use.
Instant result
Your BMI and WHO category update as you type, no button needed.
Private
Nothing is uploaded — it all runs on your device.
BMI Calculator — frequently asked questions
How is BMI calculated?
BMI = weight (kg) ÷ height (m)². For imperial it's 703 × weight (lb) ÷ height (in)². This tool does the maths for you.
What is a healthy BMI?
The WHO considers 18.5–24.9 normal. Below 18.5 is underweight, 25–29.9 overweight, and 30+ obese.
Is BMI accurate for everyone?
BMI is a quick screening guide, not a diagnosis. It doesn't account for muscle mass, age or body composition, so very muscular people can read high.
Is this BMI calculator free?
Yes — completely free, no sign-up, and it works on any device.
Share this tool
Send it to someone who needs it or save the link for later.
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