WHO growth charts are standardized graphs used worldwide to track how infants and young children grow in terms of length/height, weight, and head circumference compared with healthy peers of the same age and sex.

What is a WHO growth chart?

  • Developed by the World Health Organization using data from healthy children (0–59 months) raised in environments that support optimal growth (breastfeeding, non‑smoking mothers, good healthcare, adequate nutrition) across several countries.
  • They show percentile curves (for example, 3rd, 15th, 50th, 85th, 97th) for:
    • Length/height‑for‑age
    • Weight‑for‑age
    • Weight‑for‑length/height
    • Head circumference‑for‑age
  • The idea is: instead of asking “how do most kids grow?”, they ask “how do kids grow when conditions are ideal?”.

How they’re used in practice

Health professionals plot your child’s measurements on the chart and then follow the curve over time.

Common steps:

  1. Measure:
    • Weight (usually naked or in light clothes, infants often on an infant scale).
    • Length (lying down, “recumbent length”) for under 2 years, or standing height for older children.
 * Head circumference in infants.
  1. Calculate exact age (in days or months), which matters a lot in the first two years.
  1. Plot the point on the correct chart (boys vs girls, age group, and type of measure).
  1. Read off the percentile line it falls near (for example, 25th or 75th percentile).

What matters most is the pattern over time, not a single dot. A child who tracks along the 15th percentile consistently can be perfectly healthy; sudden drops or jumps across percentiles may need a closer look.

WHO vs CDC charts (for context)

In many countries (including the U.S.), WHO charts are recommended for 0–2 years, then clinicians switch to national reference charts (like CDC) from age 2 onward.

Key differences:

  • WHO charts:
    • Based largely on breastfed infants.
    • Show slightly faster weight gain in the first three months, then slower gain after about 3 months compared with CDC charts.
  • CDC charts:
    • Descriptive references for how U.S. children grew at the time of data collection, including more formula‑fed infants.

This means a formula‑fed infant might climb to a higher weight‑for‑length percentile on a WHO chart after 3 months and could be flagged as relatively heavier.

Quick example story

Imagine a 6‑month‑old girl:

  • Weight: 7.2 kg
  • Length: 66 cm

On the WHO weight‑for‑age and length‑for‑age charts for girls 0–2 years, she might fall around the middle percentiles (for illustration), and if she’s been following a similar curve since birth, that’s usually reassuring. If at 9 months she suddenly drops across multiple lines (say from around the 50th to below the 10th percentile), a clinician would investigate feeding, illness, or other causes.

Key mini‑takeaways

  • WHO growth charts are standards for how young children should grow in ideal conditions, not just a description of the average child.
  • Used from birth to 5 years globally; in the U.S., strongly recommended from birth to 2 years, then transition to CDC charts.
  • Percentile ≠ grade: being at the 10th or 90th percentile can both be normal if growth is steady.
  • Sudden changes in percentile lines are more concerning than being “small” or “big” once.

Simple HTML table (percentiles concept)

html

<table>
  <thead>
    <tr>
      <th>Percentile</th>
      <th>What it means</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>3rd</td>
      <td>Child is larger than about 3% of healthy peers and smaller than about 97%.</td>
    </tr>
    <tr>
      <td>50th</td>
      <td>Child is around the median; half of peers are bigger and half are smaller.</td>
    </tr>
    <tr>
      <td>97th</td>
      <td>Child is larger than about 97% of healthy peers.</td>
    </tr>
  </tbody>
</table>

If you share age, sex, and recent height/weight/head circumference, I can walk through how a clinician would interpret a specific WHO chart point (conceptually, not as a medical diagnosis).

Information gathered from public forums or data available on the internet and portrayed here.