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Pediatric BMI Percentile for children & teens.

Calculate your child's BMI percentile using CDC growth charts for ages 2–19. Instantly see whether they fall in the underweight, healthy weight, overweight, or obese range — with the formula explained.

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BMI for Children & Teens (CDC)
Pediatric BMI percentile · ages 2–19 · CDC growth charts 2000
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Child's data

yr
mo
lb
in
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Result

— BMI
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Enter child's data to see percentile
BMI kg/m²—
Percentile vs. same age & sex—
Category—
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How it's calculated

BMI + CDC percentile charts — the pediatric standard

The CDC Pediatric BMI calculator computes a child's Body Mass Index and then looks up the corresponding percentile using CDC 2000 growth chart reference data for boys and girls ages 2–19. For an 8-year-old boy who weighs 60 lb (27.2 kg) and is 50 in (127 cm) tall, BMI ≈ 16.9 kg/m², placing him near the 50th percentile — healthy weight range.

Adult BMI categories (underweight below 18.5, etc.) do not apply to children. Children's body composition changes with age and differs between boys and girls, so the same BMI value carries very different meaning at age 5 versus age 15. The CDC solution is a percentile lookup against a nationally representative reference population.

BMI = weight (kg) ÷ height (m)²
Percentile = LMS lookup for sex + exact age (CDC 2000)
  1. 1
    Convert weight and height to metric (if imperial)
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  2. 2
    Calculate BMI = kg ÷ m²
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  3. 3
    Look up L, M, S values for sex + age from CDC tables
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  4. 4
    Compute z-score and convert to percentile
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  5. 5
    Classify using CDC thresholds
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Understand the terms

BMI Percentile
A ranking that compares a child's BMI to others of the same age and sex. A child at the 75th percentile has a higher BMI than 75% of children in the reference population — not necessarily unhealthy on its own.
LMS Method
The mathematical technique used by CDC to model the distribution of BMI across ages. L (Box-Cox power), M (median), and S (coefficient of variation) parameters allow computing z-scores and percentiles at any exact age.
Pediatric Overweight
Defined by CDC as BMI at or above the 85th percentile but below the 95th percentile for children of the same age and sex. Distinguished from "obese" (≥95th percentile).
Z-score
The number of standard deviations above or below the median BMI for the reference population. Used to compute the exact percentile via the standard normal distribution.
See the full glossary →
Disclaimer: estimation tool for educational reference and health screening purposes only, using CDC 2000 growth chart reference data. BMI percentile is a screening tool — not a diagnostic measure. Many factors influence a child's healthy weight, including growth stage, muscle mass, and ethnicity. Actual classification may differ from this estimate. This calculator does not replace evaluation by a pediatrician or qualified health professional.
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Frequently asked questions — Pediatric BMI

What is BMI percentile for children?
BMI percentile compares a child's BMI to other children of the same age and sex using CDC growth charts. Because children's body fat changes with age and differs between boys and girls, percentile ranking is used instead of fixed BMI thresholds. A child at the 60th percentile has a BMI higher than 60% of children in the reference population.
How is pediatric BMI calculated?
Pediatric BMI is calculated the same way as adult BMI: weight in kilograms divided by height in meters squared (BMI = kg/m²). The critical difference is interpretation: the resulting number is then plotted on CDC sex-specific growth charts for ages 2–19 to determine the corresponding percentile.
What BMI percentile is considered healthy for a child?
According to CDC guidelines: below the 5th percentile is underweight; 5th to below 85th percentile is healthy weight; 85th to below 95th percentile is overweight; 95th percentile or above is obese. These classifications apply to children ages 2–19.
Can I use an adult BMI calculator for my child?
No. Adult BMI thresholds (underweight <18.5, healthy 18.5–24.9, etc.) do not apply to children and teens. Children's body composition changes significantly with age and sex, so the same BMI number can have very different health implications depending on the child's age and sex. Always use a pediatric percentile chart for ages 2–19.
What should I do if my child's BMI percentile is high?
A high BMI percentile (85th or above) is a screening signal, not a diagnosis. Many factors affect body composition in children, including growth spurts, muscle development, and ethnic background. Consult your child's pediatrician for a full assessment. The American Academy of Pediatrics (AAP) recommends individualized evaluation rather than any action based on BMI alone.

📚 Learn more — official sources

🏛️ Organization CDC — Clinical Growth Charts (2000) Official CDC growth chart reference tables for boys and girls ages 2–20, including BMI-for-age percentile charts used clinically across the United States. See official source → 🏛️ Organization CDC — Child & Teen BMI Calculator The CDC's own online pediatric BMI tool, with interpretation guidance based on CDC 2000 reference data and age-sex-specific percentile lookup. See official source → 🏛️ Organization WHO — Child Growth Standards World Health Organization child growth standards describing optimal growth for children under 5, widely used internationally alongside CDC charts for older children. See official source → 🔬 Study AAP Expert Committee — Pediatric Obesity Assessment and Treatment American Academy of Pediatrics expert committee recommendations on using BMI percentile in clinical practice for assessing and managing childhood obesity. See on AAP Journals →

About the Pediatric BMI Percentile Calculator

This tool calculates BMI for children and teens ages 2–19 using the same formula as adult BMI (weight in kg divided by height in m²), but interprets the result through CDC 2000 growth chart percentiles rather than fixed adult thresholds. Because children grow rapidly and boys and girls develop differently, a percentile relative to same-age, same-sex peers is the clinically accepted standard in the United States.

The percentile estimation uses a simplified LMS lookup derived from published CDC reference tables for key age points (interpolated linearly between them). The categories follow CDC definitions: underweight (below 5th percentile), healthy weight (5th–84th), overweight (85th–94th), and obese (95th and above). Always discuss results with your child's pediatrician — BMI is a screening tool, not a diagnosis.

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