BMI Calculator
Body mass index from height and weight
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About this tool
BMI (body mass index) is your weight in kilograms divided by the square of your height in meters. It does not measure body fat directly โ it shows where your weight sits relative to your height, so the same BMI can mean different things depending on muscle mass and build. Enter your height and weight and this calculator shows your BMI along with the weight range that would put you in the normal category.
How to use
- Enter your height in centimeters.
- Enter your weight in kilograms.
- BMI and its category update as you type.
- Check the bar below to see where you land and what the normal weight range is.
Frequently asked questions
- What is a normal BMI range?
- This calculator uses the Korean Society for the Study of Obesity thresholds: under 18.5 is underweight, 18.5-22.9 is normal, 23-24.9 is pre-obese (overweight), 25-29.9 is class I obesity, and 30 or above is class II or higher.
- Why does this differ from the WHO cutoffs?
- People of Asian descent tend to carry a higher body-fat percentage at the same BMI and face diabetes and hypertension risk at lower values. The Asia-Pacific thresholds therefore start overweight at 23 and obesity at 25, which is stricter than the international 25 and 30.
- Does having a lot of muscle inflate my BMI?
- Yes. BMI cannot distinguish muscle from fat, so athletic people may read high while carrying little fat. The reverse also happens: a low weight with little muscle can still mean high body fat. Waist circumference and body-fat percentage are useful companions.
- Can children or pregnant people use this?
- It is not recommended. Growing children and teenagers are assessed with age- and sex-specific growth charts, and pregnancy, older age, or muscle loss all call for different criteria.
- Is my height and weight sent to a server?
- No. Everything is calculated in your browser and your input never leaves the page.
BMI is a screening indicator, not a diagnosis. Talk to a healthcare professional about whether any change or treatment is appropriate for you.