Free tool · WHO Child Growth Standards
Baby growth percentile calculator
Check your baby's weight, length and head circumference against the WHO growth standards, from birth to 5 years.
Fill in your baby's details to see where they sit on the WHO curves. Nothing you type leaves this page.
Educational content only, not medical advice. Always talk to your doctor or health visitor about your child. A single measurement says very little. Doctors look at the pattern over several visits. Home measurements are less precise than clinic ones.
Track the whole curve, not one dot
Baby Growth Tracker Pro plots every measurement on the WHO chart, so you see the pattern your doctor looks at. It works offline and needs no account.
How to read a percentile
A percentile compares your baby with a large group of healthy babies of the same age and sex. If your daughter's weight is on the 30th percentile, 30 out of 100 healthy girls her age weigh less and 70 weigh more. The 30th is not worse than the 70th. Both are normal.
The WHO standards were built from healthy, breastfed babies in six countries, which is why most paediatricians and health visitors use them for children under 5.
What doctors actually look at
- The curve over time. A baby who follows the 10th percentile month after month is usually growing well.
- Big jumps across lines. Moving up or down two or more major lines is worth discussing with your doctor.
- Measurements far outside the usual range, below the 3rd or above the 97th percentile.
- How weight and length relate to each other, not either one alone.
See the full WHO growth charts for girls and boys, or read our guide to baby growth percentiles and how to measure your baby at home.
Where the numbers come from
This calculator uses the WHO Child Growth Standards (2006) LMS tables for weight-for-age, length/height-for-age and head-circumference-for-age, for boys and girls from birth to 1,856 days, the same data built into Baby Growth Tracker Pro. Percentiles above 2 years use standing height in the WHO tables; measure lying down before 2 and standing after.
