BMI Calculator
Calculate BMI with standard or metric measurements, adult category ranges, and age- and sex-aware guidance.
Your BMI
Enter measurements
- Height
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- Weight
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- Age and sex
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- Body fat estimate
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- BMI categories
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BMI Category BMI Range
BMI category chart
Adult BMI ranges for age 20+How to use this BMI calculator
Enter age, sex, height, and weight in standard or metric units to calculate BMI and review category guidance.
- Choose standard or metric units.
- Enter height, weight, age, and sex.
- Review the BMI value, adult category table, and any age-specific guidance.
- Use the body fat estimate as a rough screening estimate only.
What BMI means
Body mass index compares weight with height.
Adult BMI categories apply to people age 20 and older. For ages 2 through 19, BMI is interpreted using CDC age- and sex-specific percentiles.
BMI is a screening measure, not a diagnosis. A clinician can consider body composition, health history, and other measurements for personal guidance.
BMI formulas and data sources
BMI is calculated from height and weight, then interpreted using adult ranges or age-specific child and teen references.
BMI = \frac{weight_{lb}}{height_{in}^2} \cdot 703
BMI = \frac{weight_{kg}}{height_m^2}
Adult BMI categories use CDC adult BMI ranges. For ages 2 through 19, CDC BMI-for-age guidance uses percentiles based on age and sex.
The body fat percentage estimate uses published BMI, age, and sex equations from Deurenberg, Weststrate, and Seidell.