BMI Calculator

Calculate your Body Mass Index (BMI) from height and weight. Free online BMI calculator with instant category results—runs in your browser.

Everything runs in your browser. Your input is not sent to a server.

How to use the BMI Calculator

Enter your height (and select the unit if options are shown).
Enter your weight in the matching unit.
Press Calculate to see your BMI value and category.
Reset if you want to try different numbers.

How it works

BMI is weight divided by height squared (kg/m²). The tool converts units as needed and maps the result to common categories such as underweight, normal, overweight and obese.

BMI is a screening tool only—it does not diagnose health conditions. Athletes and older adults may need other measures.

Examples

Height 170 cm, weight 65 kg → BMI ≈ 22.5 (normal range).
Height 5 ft 8 in, weight 180 lb → BMI calculated after unit conversion.
Height 160 cm, weight 50 kg → BMI ≈ 19.5.

BMI Calculator FAQ

What BMI ranges are used?

Standard adult categories are typically: underweight (<18.5), normal (18.5–24.9), overweight (25–29.9), and obese (30+). Always treat BMI as a guide, not a diagnosis.

Can I use metric or imperial units?

Yes, if the form offers both. The calculator converts as required before applying the BMI formula.

Is the BMI Calculator free?

Yes. No account is needed and calculation stays in your browser.