gentle tools for your parenting journey

Growth Percentile Calculator

Enter your infant, baby or toddler's age, sex and measurements to estimate their weight, length/height and head circumference percentile, based on WHO growth standards.

Weight-for-age
Length/height-for-age
Head circumference-for-age
Estimates only, approximated from WHO Child Growth Standards medians and typical spread — not a diagnostic tool. Percentiles below the 3rd or above the 97th, or any concern about your child's growth, should always be discussed with your pediatrician.

Common questions

What does my baby's weight or height percentile mean?

A percentile shows how your baby's measurement compares to other babies of the same age and sex on the WHO growth curves. A weight-for-age result at the 40th percentile, for example, means your baby weighs more than roughly 40% of babies that age and less than the other 60%.

Is a low or high percentile a problem?

Not on its own — percentiles anywhere from around the 3rd to the 97th are generally considered within the typical range, and many perfectly healthy babies sit near either end. What pediatricians usually watch more closely is the trend over time (a baby steadily tracking along their own curve) rather than a single percentile number.

Can this estimate how big my baby will be at birth?

No — this tool estimates percentiles for babies and toddlers who have already been born, using measured weight, length and head circumference. Birth-weight estimates during pregnancy come from ultrasound measurements taken by your care provider, which this calculator doesn't do. Our Due Date Calculator and Weeks to Months Calculator can help track the pregnancy itself in the meantime.

Where do these percentiles come from?

They're approximated from the WHO Child Growth Standards, the reference charts most pediatricians use worldwide for children under 5, built from measurements of healthy, breastfed children across multiple countries.

Does this work for infants and toddlers, not just babies?

Yes — "infant," "baby" and "toddler" all fall within the 0–60 month (0–5 year) range this calculator covers. Just enter the exact age in months, whatever term you'd use for that stage, and the growth standards work the same way.