WHO vs CDC growth charts: which applies to your child?

There are two standard growth references you'll meet: the WHO Child Growth Standards and the CDC Growth Charts. In the US, the official guidance is to use WHO charts from birth to age 2, then switch to CDC charts from 2 to 20. Many other countries use WHO throughout early childhood.

Why two charts exist

The WHO standard (2006) describes how children grow under optimal conditions — breastfed, non-smoking households, good healthcare — sampled across six countries. It's prescriptive: how children should grow. The CDC chart (2000) is descriptive: how US children actually grew in past decades, bottle-fed babies and all. That's why the same toddler can land on slightly different percentiles on each chart.

Does the difference matter for you?

For a preschooler, rarely. The charts diverge most in infancy (WHO expects slower weight gain after 6 months, so fewer breastfed babies get flagged as underweight). By ages 3–6 the two references tell very similar stories, and the thing that matters — your child's trend along their own curve — reads the same on both.

The practical takeaway: use one reference consistently, measure the same way each time, and compare trends, not one-off numbers from different charts.