BMI Calculator
Calculate your Body Mass Index and see your weight category.
BMI Ranges
About the BMI Calculator
Body Mass Index (BMI) is a simple screening measure that relates your weight to your height. It's widely used by health organizations as a quick, population-level indicator, though it doesn't account for muscle mass, body composition, or individual health factors.
This calculator supports both metric (kg/cm) and imperial (lb/in) units and returns your BMI along with the standard weight category it falls into.
How to Use This Tool
- 1Enter your height and weight, choosing metric or imperial units.
- 2The calculator instantly shows your BMI value and corresponding category.
How BMI is calculated
Metric: BMI = weight (kg) ÷ [height (m)]².
Imperial: BMI = 703 × weight (lb) ÷ [height (in)]².
Standard categories: under 18.5 is underweight, 18.5–24.9 is normal weight, 25–29.9 is overweight, and 30+ is obese.
Frequently Asked Questions
Is BMI accurate for everyone?
BMI is a general screening tool and doesn't distinguish between muscle and fat, so it can be misleading for athletes, older adults, or people with unusual body composition. It's best used as one data point rather than a complete health assessment.
Is BMI different for children?
Yes — children and teens are assessed using age- and sex-specific BMI percentiles rather than the fixed adult categories used here, since body composition changes significantly during growth.
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