Calculate standard adult BMI, or include age and sex for BMI-for-age screening in children and teens.
For adults, BMI uses height and weight. Age and sex do not change the standard adult BMI formula or category thresholds.
Ages 2–19 are interpreted using sex- and age-specific CDC BMI-for-age references. Age 20+ automatically uses standard adult BMI categories.
Metric BMI is weight in kilograms divided by height in meters squared. US customary BMI uses weight in pounds and height in inches with a conversion factor of 703.
For the underlying measure, its limits and adult interpretation, see the CDC's overview of body mass index.
The BMI formula itself still uses height and weight. What changes is the interpretation. For children and adolescents, BMI is compared with people of the same age and sex using BMI-for-age percentiles. This calculator uses CDC growth-chart reference values for ages 2–19.
For adults, age and sex do not change the standard BMI category thresholds. The second calculator therefore switches to adult interpretation automatically at age 20.
No. Adult BMI is calculated and categorized using height and weight. The age field matters for children and teens because their BMI is interpreted using age- and sex-specific growth references.
For ages 2–19, BMI is compared with CDC BMI-for-age reference values for the same age and sex. Categories are based on the 5th, 85th and 95th percentile thresholds.
This calculator does not classify BMI-for-age below age 2. Growth assessment for infants and very young children uses different growth standards and should be discussed with a healthcare professional.
Enter total inches. For example, 5 feet 10 inches is 70 inches.