Calculate your child's weight, height, and BMI percentiles using WHO and CDC growth charts. Track growth from birth to age 20 with age and sex-matched comparisons.
Growth percentiles place a child's weight, height, and BMI on age- and sex-specific reference charts. That helps show whether current measurements are tracking along a familiar pattern or whether a follow-up question is worth bringing to a clinician.
For ages 0–2, this page uses the WHO growth standards. For ages 2–20, it uses the CDC growth charts commonly used in U.S. practice. Looking at weight-for-age, height-for-age, and BMI-for-age together gives more context than any one measure on its own.
This calculator is best used as a structured way to log measurements between visits and to understand which percentile each measurement falls into before discussing the result with your pediatrician.
This worksheet helps you organize a child's measurements and see how weight, height, and BMI compare on the relevant chart. It is useful for noticing trends between appointments, but it should support clinical follow-up rather than replace it.
BMI = weight(kg) / height(m)² Percentile calculation uses the LMS method: z-score = ((measurement / M)^L − 1) / (L × S) where L = power, M = median, S = coefficient of variation Percentile = Φ(z) × 100 (standard normal CDF) Weight-for-age: WHO 0–2 yr, CDC 2–20 yr Height-for-age: WHO 0–2 yr, CDC 2–20 yr BMI-for-age: WHO 0–2 yr (weight-for-length), CDC 2–20 yr
Result: Weight: 55th | Height: 42nd | BMI: 57th percentile
An 8-year-4-month-old girl weighing 58 lbs and measuring 50 inches falls at the 55th percentile for weight (average), 42nd for height (average, slightly below midline), and 57th for BMI (healthy weight). All three metrics are within the normal range (5th–85th) and proportionate to each other, indicating healthy, balanced growth.
Weight-for-age alone can be misleading — a tall child will naturally weigh more. Height-for-age alone misses nutritional status. BMI-for-age combines both but can't distinguish muscle from fat. By tracking all three together, you get the most complete picture of your child's growth. A child at the 80th percentile for weight, 80th for height, and 50th for BMI is proportionally large — perfectly healthy.
While percentiles show where your child is relative to peers, growth velocity shows how fast they're growing. Normal growth velocity varies by age: infants gain 5–7 inches/year, toddlers 3–5 inches/year, school-age children 2–3 inches/year, and puberty brings another 3–4 inches/year. Abnormally slow growth velocity warrants investigation even if the current percentile appears "normal."
Bring growth concerns to your pediatrician if: your child crosses two major percentile lines in either direction, BMI is above the 95th or below the 5th percentile, growth appears to have stalled (no height increase in 6+ months outside of puberty pauses), or there's a significant discrepancy between height and weight percentiles (e.g., 90th weight, 20th height).
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This worksheet converts age, sex, weight, and height into percentiles using the WHO growth standards for ages 0 to 2 years and CDC growth charts for ages 2 to 20 years. Percentiles are derived from LMS-based z-scores, then mapped back to percentile ranks. The result is a reference-chart comparison, not a diagnosis.
For children ages 2–20, CDC categories are: Underweight = below 5th percentile, Healthy weight = 5th to 84th percentile, Overweight = 85th to 94th percentile, Obese = 95th percentile and above. Note that these categories are different from adult BMI categories, which use fixed BMI cutoffs rather than percentiles.
Not necessarily. A child who has always tracked near the 10th percentile is simply smaller than average, which is perfectly normal. Concern arises if a child's percentile drops significantly (e.g., from 50th to 10th over 6–12 months), which could indicate a growth or nutritional issue. Genetics play a major role — smaller parents tend to have smaller children.
The WHO growth standards are recommended for children 0–2 years (based on breastfed babies, representing how children should grow). The CDC growth charts are used for ages 2–20 years in the U.S. (representing how children did grow). Some practitioners use WHO charts through age 5. The key difference: WHO charts show slightly higher growth in the first months and lower from 3–12 months compared to CDC.
Puberty causes major shifts: early developers may temporarily jump to higher height percentiles, while late developers may appear to fall behind. Girls typically begin puberty at ages 8–13 and reach adult height by 14–16. Boys begin at 9–14 and may grow until 16–18. These timing differences can cause significant temporary percentile changes that normalize by adulthood.
A BMI above the 95th percentile meets the clinical definition of childhood obesity. However, this doesn't mean your child needs to "diet" — children are growing, so the goal is usually to slow weight gain while height catches up, rather than active weight loss. Focus on increasing fruits, vegetables, whole grains, and physical activity. Consult your pediatrician for a personalized plan.
At-home measurements can vary by 0.5–1 inch, which significantly affects percentile accuracy, especially for shorter children. For best results: measure in the morning (children are taller), use a flat wall and hard floor, ensure heels/buttocks/shoulder blades touch the wall, use a flat object on the head to mark the spot, and measure three times, using the average.