← All tools

BMI Calculator

Calculate your Body Mass Index instantly using metric or imperial units.

UnderweightHealthyOverweightObese
For general information only. BMI is a simple screening measure and doesn't account for muscle mass, bone density, age, sex, or ethnicity. It is not a diagnosis — consult a healthcare professional for a full assessment of your health.

About BMI

Body Mass Index (BMI) is a simple calculation using your height and weight, used as a rough screening tool to categorize weight ranges that may lead to health problems. It's calculated as weight (kg) divided by height (m) squared.

Standard BMI categories (WHO)

BMI RangeCategory
Below 18.5Underweight
18.5 – 24.9Healthy weight
25.0 – 29.9Overweight
30.0 and aboveObese

Limitations

BMI doesn't distinguish between muscle and fat, so athletic or muscular individuals may show a higher BMI despite having low body fat. It's a population-level screening tool, not a precise individual diagnostic — use it as a general reference point rather than a definitive health measure.

Frequently Asked Questions

Is BMI accurate for athletes?

Not particularly — BMI doesn't distinguish muscle from fat, so muscular or athletic individuals often show a higher BMI despite low body fat.

Does BMI differ for men and women?

The standard BMI formula and category thresholds are the same for both sexes, though some health organizations note that body fat distribution differs by sex as a limitation of the measure.

What should I do if my BMI is outside the healthy range?

Talk to a healthcare professional — they can assess your specific situation far more accurately than a general screening number alone.