Growth Chart Percentile Calculator
Calculate height-for-age and weight-for-age percentiles for children 2-20 using CDC growth reference data. Track growth patterns and identify potential concerns.
Pediatric BMI Percentile Calculator
Calculate BMI-for-age percentile for children ages 2-20. Classify weight status using CDC growth chart categories: underweight, normal, overweight, and obese.
⚠️ Medical Disclaimer: This calculator provides approximate percentiles for educational purposes. Actual clinical assessment requires plotting on CDC or WHO growth charts by a healthcare provider. This tool does not replace pediatric evaluation.
years
kg
cm
BMI Percentile for 10-Year-Old Boy
75th
Healthy Weight
BMI: 17.9 | z-score: 0.66
BMI⧉
17.9
z-score: 0.66
Percentile⧉
74.5th
Healthy Weight
50th %ile BMI⧉
16.7
Median for age/sex
Percentile Scale
75
5thHealthy85th95th
BMI Cutoffs for 10-Year-Old Boys
| Percentile | BMI | Category |
|---|---|---|
| 5th | 14.1 | Underweight threshold |
| 50th | 16.7 | Median |
| 85th | 18.6 | Overweight threshold |
| 95th | 19.8 | Obesity threshold |
| This child | 17.9 | 74.5th %ile — Healthy Weight |
CDC Weight Status Categories
| Percentile Range | Weight Status | Action |
|---|---|---|
| < 5th | Underweight | Nutritional assessment, rule out medical causes |
| 5th–84th | Healthy Weight ◀ | Continue healthy habits; annual monitoring |
| 85th–94th | Overweight | Lifestyle counseling, screen for comorbidities |
| ≥ 95th | Obese | Comprehensive evaluation, labs, family-centered plan |
| ≥ 120% of 95th | Severe Obesity | Urgent referral; consider intensive intervention |
Planning notes, formulas, and examples
About the Pediatric BMI Percentile Calculator
The Pediatric BMI Percentile Calculator determines where a child's BMI falls relative to other children of the same age and sex using CDC growth reference data. Unlike adult BMI, children's BMI is interpreted using age- and sex-specific percentile charts because body composition changes dramatically during growth and puberty.
A child's BMI at the 85th percentile means their BMI is higher than 85% of same-age, same-sex peers in the reference population. The CDC categorizes children as underweight (< 5th percentile), healthy weight (5th–84th), overweight (85th–94th), and obese (≥ 95th percentile). Extended categories include severe obesity (≥ 120% of the 95th percentile).
This calculator is intended for children ages 2–20 years. For infants under 2, weight-for-length charts should be used instead.
When This Page Helps
BMI percentile is commonly used in pediatric screening because a child's BMI has to be interpreted against age- and sex-specific growth data. This calculator can help families or clinicians estimate where a child falls on that chart between visits, while keeping the result in the broader context of growth history and clinical review.
How to Use the Inputs
- Enter the child's age in years (2–20).
- Select the child's sex.
- Enter their weight in kilograms.
- Enter their height in centimeters.
- View the calculated BMI and percentile.
- See the weight status classification.
- Review the percentile range chart.
Formula used
BMI = Weight (kg) / Height (m)²
Percentile is determined by comparing the BMI to the CDC 2000 growth reference data using the LMS (Lambda-Mu-Sigma) smoothing method:
z = [(BMI/M)ᴸ − 1] / (L × S)
Where L, M, S are age- and sex-specific parameters.
Percentile = Φ(z) × 100 (standard normal CDF)
WHO Classification for children 2–20:
• Underweight: < 5th percentile
• Normal weight: 5th–84th percentile
• Overweight: 85th–94th percentile
• Obese: ≥ 95th percentile
• Severely obese: ≥ 120% of 95th percentile BMIExample Calculation
Result: BMI = 17.9, ~60th percentile — Healthy Weight
BMI = 35 / (1.40)² = 35 / 1.96 = 17.9. For a 10-year-old male, a BMI of 17.9 falls approximately at the 60th percentile based on CDC growth charts. This is within the healthy weight range (5th–84th percentile), meaning the child has a higher BMI than about 60% of same-age boys but is well within normal limits.
Tips & Best Practices
- BMI percentile should be tracked over time — a single measurement is a snapshot, but the trend reveals growth trajectory.
- An upward crossing of percentile lines (e.g., from 60th to 90th) warrants attention even if still in the "normal" range.
- BMI does not distinguish between muscle and fat mass — very athletic children may have higher BMI without excess fat.
- For children under 2, use the WHO weight-for-length chart instead of BMI-for-age.
- Cultural sensitivity is important when discussing weight with families — focus on health behaviors, not just numbers.
- The 85th percentile cutoff for overweight corresponds roughly to an adult BMI of 25 when projected forward.
The CDC Growth Reference
The CDC 2000 growth charts were derived from five national health examination surveys conducted between 1963 and 1994. They represent how American children grew during that period and serve as a reference (not a standard). The LMS parameters at each age allow smooth interpolation of percentiles and z-scores.
Severe Obesity Classification
In 2013, the AHA released a statement recommending further classification of childhood obesity severity: Class I (95th to 119% of 95th percentile), Class II (120% to 139% of 95th), and Class III (≥ 140% of 95th or BMI ≥ 40). Severe obesity is associated with higher cardiometabolic risk even in childhood.
Tracking Over Time
Single BMI percentile measurements provide limited information. Plotting BMI percentile longitudinally on growth charts reveals patterns such as adiposity rebound (the normal rise in BMI after its nadir around age 5–7) and excessive percentile crossing. Early adiposity rebound (before age 5) is a risk factor for later obesity.
Sources & Methodology
Last updated:
Methodology
This calculator computes BMI from the entered height and weight, then maps that BMI to the CDC BMI-for-age growth reference using age- and sex-specific LMS parameters. It reports the corresponding percentile band and, when relevant, the severe-obesity framing based on percent of the 95th percentile.
The result is a screening aid rather than a stand-alone diagnosis. Pediatric weight status still needs to be interpreted with longitudinal growth pattern, puberty stage, family history, and the rest of the clinical assessment.
Sources
- Child and Teen BMI Calculator (CDC) — Official CDC calculator using BMI-for-age percentiles for ages 2 through 19 years.
- Summary and References: Using BMI-for-Age Growth Charts (CDC) — Clinical overview of how BMI-for-age percentiles are used and interpreted.
- Extended BMI-for-Age Growth Charts (CDC) — CDC reference for severe-obesity framing above the 95th percentile.
Frequently Asked Questions
Children's body fat percentage changes with age and differs between boys and girls, especially during puberty. A BMI of 22 might be normal for a 15-year-old boy but overweight for an 8-year-old girl. Age- and sex-specific percentiles account for these developmental changes.
The WHO charts (2006) describe how healthy breastfed children should grow and are recommended for children 0–2 years. The CDC charts (2000) describe how US children did grow and are used for children 2–20. In practice, pediatricians use WHO for infants and CDC for older children.
Yes. BMI cannot distinguish muscle from fat. An athletic child with above-average muscle mass may plot at a higher percentile without having excess body fat. In these cases, a clinical assessment (including body composition, family history, and health markers) provides a more complete picture.
A BMI at or above the 95th percentile indicates obesity and warrants a conversation with your pediatrician. They will assess contributing factors (diet, activity, genetics, medical conditions), screen for complications (prediabetes, lipids, blood pressure), and develop a family-centered plan. The goal for growing children is often to slow weight gain while height catches up.
BMI percentile is a useful screening tool but not a diagnostic test. It has good sensitivity and specificity for excess body fat at the population level, but individual children may be misclassified. Waist circumference, skinfold thickness, or body composition testing can supplement BMI when clinical concern exists.
Children with obesity, especially after age 6, have a significantly higher risk of adult obesity. A child at the 95th percentile at age 10 has roughly an 80% chance of being obese as an adult. However, early intervention can change this trajectory — which is why screening matters.
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