Baby Growth Percentile

Enter your baby’s age, sex and measurements to see their percentiles against the WHO Child Growth Standards — the international reference for how breastfed babies grow. A percentile simply shows how your baby compares with others the same age and sex.

Age (months)

Weight (kg)Length (cm)Head (cm)

Based on WHO Child Growth Standards, for general information only — not medical advice or a diagnosis. Your provider should measure your baby and interpret growth over time.

How it works

The WHO growth standards describe how healthy children grow in optimal conditions, and are used worldwide for babies up to age 5. We compute an exact z-score and percentile from the official WHO data for weight-for-age, length-for-age and head-circumference-for-age (0–24 months).

A percentile is not a grade. A baby on the 15th percentile is perfectly healthy — it just means about 15 in 100 babies the same age weigh less. What matters most is that your baby follows their own curve steadily over time, which only your provider can track properly.

Frequently asked questions

What does a percentile mean? +

If your baby is on the 60th percentile for weight, they weigh more than about 60 of every 100 babies the same age and sex. Any percentile from low to high can be perfectly healthy — there’s no “good” or “bad” number.

My baby is on a low percentile — is that bad? +

Not on its own. Healthy babies sit across the whole range. Providers watch the trend over time rather than a single point — a baby steadily following the 10th percentile is usually doing fine.

Which growth chart does this use? +

The WHO Child Growth Standards, which describe how healthy, breastfed babies grow and are recommended internationally for ages 0–5. Some countries use other charts (e.g. CDC after age 2), so numbers can differ slightly.

Should I worry if a percentile changes? +

Small shifts are normal. A large, sustained jump or drop across percentile lines is worth discussing with your provider, who can measure accurately and see the full picture.