Calculate your Body Mass Index (BMI) using metric or imperial measurements. BMI is a simple screening tool to indicate whether you are at a healthy weight for your height.
BMI Calculator
BMI Categories
| BMI Range | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obese |
How BMI Is Calculated
Metric: BMI = weight (kg) ÷ height (m)²
Imperial: BMI = (weight (lbs) ÷ height (in)²) × 703
Frequently Asked Questions
Is BMI an accurate measure of health?
BMI is a useful screening tool but has limitations. It does not distinguish between muscle and fat, so muscular individuals may score high without excess body fat. It also does not account for age, sex, or fat distribution.
What BMI is considered healthy?
For most adults, a BMI between 18.5 and 24.9 is considered healthy. Ranges can differ by age and ethnicity — some organizations use lower cutoffs for people of Asian descent.
Can BMI be used for children?
This calculator is for adults 20+. For children and teens, BMI is assessed using age- and sex-specific growth charts (BMI-for-age percentiles) to account for natural changes during growth.
What should I do if my BMI is outside the normal range?
BMI is a starting point, not a diagnosis. Consult a healthcare professional for a complete assessment including waist circumference, blood pressure, cholesterol, and lifestyle factors.
Why does the imperial formula use 703?
The factor 703 converts the result from lbs/in² to the standard kg/m² unit, accounting for the conversions between pounds and kilograms and between inches and meters.