BMI Calculator
Calculate your body mass index from height and weight in metric or imperial units, with the WHO category, your healthy weight range, and a visual scale. Nothing is stored.
How to Use
- Choose your unit system — Metric (cm, kg) or Imperial (ft, in, lb).
- Enter your height and weight.
- Click Calculate BMI.
- Read your BMI, WHO category, healthy weight range, and where you sit on the scale.
- Use Copy result to save it, or Reset to start over.
Example
Metric: 170 cm, 65 kg → BMI 22.5, Normal, healthy range 53.5–72.0 kg
Imperial: 5 ft 7 in, 143 lb → BMI 22.4, Normal
Overweight: 160 cm, 75 kg → BMI 29.3, about 11.3 kg above the healthy range
Example numbers are illustrative — enter your own measurements for your result.
Frequently Asked Questions
How is BMI calculated?
BMI is weight divided by height squared. In metric units: BMI = kg / m². In imperial units: BMI = 703 × lb / in². The result is a number that lets you compare your weight against standard adult categories.
What do the categories mean?
The World Health Organization defines adult categories as: underweight below 18.5, normal weight 18.5 to 24.9, overweight 25.0 to 29.9, and obese 30.0 or above. These cutoffs apply to adults aged 20 and over.
Are different cutoffs used for South Asian bodies?
Yes. Research shows that people of South Asian origin face higher risks of diabetes and heart disease at a lower BMI. Many health bodies use 23.0 as the overweight cutoff and 27.5 as the obese cutoff for Asian populations — so a result between 23 and 25 may deserve attention even though it reads as “normal” here.
What are the limitations of BMI?
BMI does not distinguish muscle from fat, so very muscular people can score “overweight” while being lean. It is also not valid for children, teenagers, pregnant women, or athletes — those groups need age-, sex-, and context-specific measures instead.
How is my healthy weight range calculated?
It is the weight range that puts your BMI between 18.5 and 24.9 at your height: multiply your height in metres squared by 18.5 for the minimum and by 24.9 for the maximum (the imperial formula uses 703 and inches).
Is my height or weight stored anywhere?
No. The calculation runs entirely in this browser tab. Nothing is uploaded, logged, or saved — close the tab and it is gone.