Why is child BMI evaluated as a percentile rather than a fixed number?

Because children's body composition changes rapidly as they grow and differs significantly between boys and girls, pediatric BMI must be evaluated relative to other children of the exact same age and biological sex.

What do the four official CDC pediatric weight categories mean?

Underweight is defined as a BMI below the 5th percentile; Healthy Weight is between the 5th and 85th percentiles; Overweight is between the 85th and 95th percentiles; and Obesity is at or above the 95th percentile.

Is this calculator suitable for infants under 2 years old?

No. Children under age 2 should be evaluated using WHO weight-for-length growth charts rather than standard BMI calculations.

Does FreeToolsBox log my child's age, gender, or weight measurements?

No. All pediatric calculations occur 100% in local browser memory with zero external data collection.

Health & Calculators

BMI Percentile Calculator for Kids & Teens

Estimate BMI-for-age percentiles for children and teens ages 2–19 using a simplified educational reference model.

Medical Disclaimer: This educational estimate uses age-in-years median and spread values, not the official CDC LMS tables. It is not a clinical percentile or a substitute for professional medical advice. Consult a pediatrician for proper assessment of a child's growth and health.

Unit System

Sex

Age (2–19 years)

Weight

Height

BMI Percentile (Age 10)

33.4th

Healthy Weight

BMI: 17.9 kg/m²

What this means:

Between the 5th and 85th percentile — healthy range.

CDC Percentile Scale

Under-weight <5thHealthy 5–85thOver-wt 85–95thObese ≥95th

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What is BMI Percentile Calculator for Kids & Teens?

The Child BMI Estimator calculates BMI and an age-and-sex-specific educational percentile estimate for children and teenagers aged 2 to 19 years. It uses a simplified reference model rather than the official CDC LMS dataset, so results are for learning only and should be reviewed with a pediatrician.

Designed for accuracy, speed, and privacy, this tool runs entirely on your local device with zero network latency.

How to Use the BMI Percentile Calculator for Kids & Teens

1
Select your preferred measurement unit: Metric (cm, kg) or Imperial (ft, in, lbs).
2
Select your child's biological sex (Boy / Girl) and exact age in years (ages 2 to 20).
3
Enter your child's height and current weight.
4
View the BMI, estimated percentile and broad weight category. Treat the result as an educational estimate, not an official CDC growth-chart result.

Formula & Calculation Logic

Calculates pediatric BMI and an approximate percentile using a simplified age-in-years median and spread table. The widget does not contain the official CDC LMS reference values or month-level interpolation required for clinical growth-chart percentiles.

BMI = Weight(kg) / (Height(m))^2 | z ≈ (BMI − age/sex median) / reference spread | Percentile ≈ Normal_CDF(z)

BMI Percentile Calculator for Kids & Teens Frequently Asked Questions

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