Growth percentile calculator
Weight, length or height, and head circumference, on the CDC's own charts.
The CDC recommends the WHO growth standards from birth to age 2 and the CDC growth charts from 2 to 20, and publishes their tables. This calculator uses those tables to find a percentile. It runs in your browser, so your child's details never leave your device.
Checked October 29, 2026.
Enter a birth date and at least one measurement.
Nothing you type here leaves your device. Nothing is saved.
How it works
It looks up the CDC's L, M and S values for your child's sex and age, and uses the CDC's own formula to turn a measurement into a z-score and then a percentile. Ages between the tables' rows are worked out on a straight line between the two nearest rows, as the CDC's notes allow. Head circumference has a chart only to 24 months.
What it does not do
It does not say whether a child is healthy. It does not adjust for early birth. One percentile says little; the trend over time matters most. Read what percentiles mean and don't.
Call your pediatrician if…
Ask your pediatrician to read your child's growth trend with you. More from the AAP and the CDC:
Sources
- CDC: Growth Charts, Recommendations and Rationale (WHO standards to age 2, CDC charts from 2) (checked October 29, 2026)
- CDC: WHO Growth Charts Data Files (LMS parameters, birth to 24 months) (checked October 29, 2026)
- CDC: CDC Growth Charts Data Files (LMS parameters, 2 to 20 years) (checked October 29, 2026)
- AAP, HealthyChildren.org: Understanding Growth Charts, a Parent's Guide to Percentiles (checked October 29, 2026)