WHO vs CDC Growth Charts: Which to Use in 2026

If you have compared two growth charts and gotten two different percentiles for the same baby, you have run into one of the most confusing facts in infant health: there is more than one standard. The two you will encounter are the WHO charts and the CDC charts. They are built differently, they answer slightly different questions, and the choice affects your baby's percentile. This guide explains the difference in plain language and helps you pick. You can run either reference through our free growth percentile calculator.

The short answer

For babies and toddlers from birth to 24 months, major health authorities, including the CDC itself, recommend using the WHO growth charts. For children aged 2 and older, the CDC charts are typically used. So for the 0 to 24 month window this calculator covers, WHO is the standard recommendation, with CDC available as a reference.

What each chart actually is

WHO charts: a growth standard

The World Health Organization charts are a growth standard. They describe how children should grow under optimal conditions. They were built from a large international study of healthy children across several countries who were raised in recommended conditions, including breastfeeding and good nutrition. Because they describe ideal growth, they act as a prescriptive benchmark: this is what healthy growth looks like.

CDC charts: a growth reference

The Centers for Disease Control and Prevention charts are a growth reference. They describe how children in a particular population actually grew, based largely on historical survey data from the United States. Because they reflect how children did grow rather than how they ideally should, they are descriptive rather than prescriptive. For older children and for clinical continuity beyond age 2, the CDC charts remain the standard tool in the United States.

Why the two give different percentiles

The most discussed difference involves breastfed babies. The WHO sample was based on infants fed in line with current recommendations, with breastfeeding as the norm. Breastfed babies tend to gain weight a bit faster in the very early months and then a bit more slowly later in the first year compared with the patterns baked into older reference data.

The practical result: a healthy breastfed baby measured against the CDC reference can appear to be "falling off" their weight curve in the second half of the first year, when in fact they are growing exactly as a healthy breastfed baby should. Measured against the WHO standard, the same baby tracks normally. This is a major reason the WHO charts are preferred under age 2: they reduce the risk of mistaking normal breastfed growth for faltering growth, and the unnecessary worry, extra testing, or pressure to overfeed that can follow.

Other differences

• Population. WHO is international and condition-controlled; CDC is largely US survey-based.
• Purpose. WHO sets a goal for healthy growth; CDC describes observed growth.
• Curve shape. The two diverge most for weight in infancy, which is exactly the window where the choice matters most.

Which should you use?

1. Birth to 24 months: use the WHO charts. This is the recommended standard and the one most pediatricians apply for this age.
2. Age 2 and up: transition to the CDC charts, which align with how growth is tracked through childhood in the US.
3. Follow your clinic. If your pediatrician's records use a particular chart, match it so your trend lines stay consistent over time. A consistent chart matters more than the brand of chart.

The single biggest mistake is comparing a percentile from one standard against a percentile from the other and concluding something has changed. The baby did not change; the ruler did. Always compare like with like.

What does not change between the charts

No matter which standard you use, the core principles hold. The trend over time matters more than any single percentile. Healthy babies fill the whole range. Weight, length, and head circumference are read together, not in isolation. And the chart is one input that your pediatrician combines with feeding history, development, and a physical exam. Switching from WHO to CDC will shift the exact percentile, but it will not change whether your baby is growing steadily along their own curve, which is the thing that actually matters.

When to talk to your pediatrician

Regardless of chart, raise concerns if your baby crosses two or more major percentile lines up or down over consecutive visits, if the weight curve flattens, if feeding is difficult, if wet diapers drop off, or if head circumference moves very differently from weight and length. Bring the question of which chart your clinic uses to your next visit so you and your pediatrician are reading from the same map.

This article is general educational information, not medical advice. The choice of chart and the interpretation of growth should be made with your pediatrician, who sees the full clinical picture. Always consult them about your baby's growth.

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