BMI Calculator
Calculate your Body Mass Index (BMI) from weight and height and see your weight category. Free and private, right in your browser.
Enter your weight and height to get your BMI instantly, along with which standard category (underweight, normal, overweight, obesity) it falls into, handy for a quick health checkup, tracking progress over time, or filling out a form that asks for it.
How to use it
- Enter your weight and height (metric or imperial)
- View your BMI number and category instantly
- Adjust the values to see how BMI changes
Frequently asked questions
- BMI vs BMI prime. What's the difference?
- BMI is your weight divided by height squared (kg/m²). BMI prime is that number divided by the upper healthy-weight threshold (25), so a BMI prime of 1.0 sits right at the boundary, useful if you want a quick sense of how far from "normal" a value is, not just which bucket it falls into.
- Why does my BMI look off for someone very muscular or very short?
- BMI only uses weight and height, so it can't tell muscle from fat. Athletes often land in "overweight" despite low body fat, and very short or very tall people can get skewed numbers because the formula doesn't scale perfectly across the full height range. Treat it as a screening number, not a diagnosis.
- Does it work with pounds and inches, or only metric?
- Both. Enter kilograms/centimeters or pounds/feet-and-inches and the calculator converts automatically, so you don't need to do the 703x conversion math yourself.
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Nothing is uploaded
The file never leaves your device. There is no server to send it to, so there is nothing to leak, log, or subpoena.
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No signup, no limits
No account, no email, no daily cap, no watermark, and no paid tier waiting behind the third file.
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Works offline
Load the page once and it keeps working with the network off, because all the work was always happening locally.