BMI Calculator
Find your Body Mass Index, weight category, and healthy weight range in metric or imperial units — instantly and privately.
About this calculator
Body Mass Index (BMI) is a simple screening number that estimates whether your weight is in a healthy range for your height. It is calculated by dividing your weight in kilograms by the square of your height in metres. This free BMI calculator works in both metric and imperial units and instantly shows your BMI, the official WHO weight category, where you fall on the BMI scale, and the healthy weight range for your height.
BMI is useful as a quick, population-level indicator, but it has real limitations: it does not distinguish muscle from fat, and it does not account for age, sex, bone density, or body-fat distribution. Athletes and very muscular people may register as overweight despite being healthy, while others within the normal range may still carry excess fat. Treat BMI as a starting point, not a diagnosis. Everything is calculated locally in your browser, and for any health decisions you should consult a qualified healthcare professional.
Why use this tool
Instant BMI + category
Get your body mass index and where it falls (underweight to obese).
Metric or imperial
Enter height and weight in the units you prefer.
Healthy range
See the weight range considered healthy for your height.
Common use cases
- Check your BMI quickly
- Track progress towards a healthy weight
- See your healthy weight range
- Compare BMI before and after a fitness plan
Frequently asked questions
The World Health Organization considers a BMI of 18.5 to 24.9 to be the normal, healthy range for most adults. Below 18.5 is underweight, 25–29.9 is overweight, and 30 or above is classified as obese.
Not always. BMI only uses height and weight, so it can misclassify very muscular people (such as athletes) as overweight because muscle weighs more than fat. For them, body-fat percentage is a better measure.
BMI estimates whether your weight is healthy for your height, while body-fat percentage measures the proportion of your body that is fat. Two people with the same BMI can have very different body compositions.
In metric, BMI = weight in kilograms ÷ (height in metres)². In imperial, BMI = (weight in pounds ÷ (height in inches)²) × 703. This calculator does both for you instantly.
Use whichever you know your measurements in — the result is identical. Toggle between Metric (kg/cm) and Imperial (lbs/ft) at the top of the calculator.