CDC Growth Charts (0-36 Months)

Head Circ-for-Age (CDC 0-3)

z = (HC − μ) / σ

Head circumference percentile against CDC reference.

Calculate Percentile

The CDC 0-36 month growth charts are the U.S.-historical reference for infants and toddlers, based on growth patterns observed in a U.S. sample. The CDC charts are widely used in U.S. clinical practice though the WHO standards (also on this site) are now recommended for 0-24 months.

Each calculator returns a CDC-referenced percentile and z-score, plus the visual placement on the CDC percentile curves.

When to use these calculators

The CDC charts describe how U.S. children have grown; the WHO standards describe how children should grow under optimal conditions. For 0-24 months WHO is preferred per AAP and WHO joint guidance; for 24+ months CDC is conventional in U.S. practice.

Frequently Asked Questions

Why use CDC if WHO is recommended?
Many U.S. EMRs, public-health programs, and clinical references still use CDC charts as the default. The CDC charts are valid; they're descriptive rather than prescriptive. Use whichever your institution prescribes.
What's the practical difference between CDC and WHO percentiles?
Breastfed infants tend to track higher percentiles on the WHO charts than on the CDC charts, especially in the first 6 months. This is because the WHO sample was composed of optimally-fed (largely breastfed) infants, while the CDC sample reflects mixed feeding.
Why does the CDC chart only go to 36 months?
From age 2-3, U.S. practice transitions to the CDC 2-20 year chart (also on this site). The 0-36 month chart overlaps with the 2-20 chart from 24-36 months for a smooth handoff.