Length-for-Age Percentile Calculator (CDC, 0-36 Months)

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More CDC (0-36 Months) Charts

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For educational purposes only. Not a substitute for professional medical advice. Consult your pediatrician for growth concerns.

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How Length-for-Age Percentiles Work (CDC, 0-36 Months)

This calculator uses CDC growth reference data, recommended for monitoring growth in the United States. Length-for-age percentiles help assess whether your child’s length (or height) is within the expected range for their age and sex.

The calculator uses the LMS method (Lambda-Mu-Sigma), a statistical technique that models the distribution of length at each age. Lambda (L) accounts for skewness, Mu (M) is the median, and Sigma (S) is the coefficient of variation.

CDC vs. WHO Growth Charts

The CDC recommends using WHO growth standards for children under 2 years and CDC growth charts for children aged 2 to 20 years. The CDC 0-36 month length-for-age charts provide a reference based on U.S. population data and remain commonly used in clinical settings.

Understanding Length-for-Age Percentiles

A percentile indicates the percentage of children who are shorter than your child. For example, a child at the 60th percentile is longer than 60% of children of the same age and sex.

  • 3rd to 97th percentile is considered the normal range
  • Below the 3rd percentile may indicate short stature
  • Above the 97th percentile may indicate tall stature
  • The growth trend is more important than a single measurement

Example Calculation

A newborn boy measuring 49.99 cm in length would be approximately at the 50th percentile, since the CDC median length for boys at birth is about 49.99 cm.

Frequently Asked Questions

What age range does this calculator cover?

This calculator uses CDC growth reference data for children from birth to 35.5 months. The CDC data uses half-month intervals for precise tracking during rapid growth.

Should I measure length or height?

For children under 2 years, use recumbent length (measured lying down). For children 2 years and older, standing height is typically used. Standing height is about 0.7 cm shorter than recumbent length.

How is this different from the WHO calculator?

The WHO growth standards describe optimal growth based on breastfed children from multiple countries. The CDC charts describe how U.S. children actually grew, including both breastfed and formula-fed infants.

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