All 3 percentile calculators on QuickCalcHub — free, instant, no signup.
A growth percentile says where a child sits within a reference population of the same age and sex — it is a comparison, not a diagnosis. The 50th percentile is the median, not a target; a child who tracks steadily at the 10th percentile from age three to age ten is growing perfectly consistently, while a child who drops from the 60th to the 10th in six months is the one worth investigating. That is why pediatric practice reads the curve, not a single point.
| Age | Correct reference | Why |
|---|---|---|
| 0–2 years | WHO growth standards | CDC and the AAP recommend WHO charts for under-2s because they describe how healthy, breastfed infants grow rather than how a mixed US sample grew. |
| 2–20 years | CDC 2000 growth charts | The reference used on this page, and the one US pediatric offices plot against past age 2. |
Mixing the two produces a visible step at age 2, which is exactly the artefact the CDC warns about. If your child is close to that boundary, keep every measurement on the same chart.
| Measure | Use | Notes |
|---|---|---|
| BMI-for-age | Child BMI Percentile Calculator | The CDC-recommended screening measure from age 2 |
| Height-for-age | Child Height Percentile Calculator | Stature percentile, median height and 3rd–97th range |
| Weight-for-age | Child Weight Percentile Calculator | Useful for tracking, but cannot tell muscle from fat |
The reference values come from the CDC 2000 growth charts, published by the US Centers for Disease Control and Prevention. The CDC publishes them as LMS parameters, which are the official way to describe a growth distribution that is skewed rather than normally distributed. From the three parameters:
M is the median (the 50th percentile value), S is the coefficient of variation and L is the skewness power that bends the distribution into the right shape. The percentile is then the standard normal cumulative distribution at z: percentile = Φ(z) × 100.
Age is interpolated linearly between the published half-month rows, then rounded to the nearest half month. Interpolation in the middle of a 0.5-month gap introduces far less error than the measurement error of a home height or weight reading, which is typically 0.5–1 cm and 0.1–0.2 kg.