Enter your baby’s sex, age and measurements to see their weight and length percentiles compared with WHO growth standards. This free baby percentile calculator is designed for babies aged 0–24 months and explains the result in plain English, so you can see at a glance how your baby compares with babies of the same age and sex.
Baby Percentile Calculator
What do percentiles mean?
A percentile compares your baby with other babies of the same age and sex. The 50th percentile is the average: half of babies are bigger and half are smaller. A child at the 75th percentile is bigger than 75 out of 100 babies of the same age and sex — and smaller than the other 25.
Percentiles are not grades, and higher is not better. A baby at the 15th percentile who follows that curve steadily is usually growing just as well as a baby at the 85th percentile. What matters most is steady growth along a curve over time, not any single measurement on a single day.
Talk with your pediatrician if your baby crosses two major percentile lines on the growth chart, stays below the 3rd percentile or above the 97th percentile, or if you are ever worried about feeding, growth or development. Only your own doctor can judge your baby's growth in full context.
More baby tools and guides
Start with our baby age calculator to find your baby's exact age in weeks and months, check length on its own with the height percentile calculator, and see the full picture on the baby growth chart page.
Frequently asked questions
What is a good percentile for a baby?
There is no single good percentile. Healthy babies grow at many different sizes, and a percentile anywhere from the 3rd to the 97th can be normal. What matters most is that your baby follows a steady growth curve over time and is feeding and developing well.
Is the 50th percentile ideal?
No. The 50th percentile is simply the average — half of babies are above it and half are below it. It is not a target to aim for, and a baby does not need to be at the 50th percentile to be perfectly healthy.
Should I worry if my baby's percentile drops?
Small moves between percentiles are common and are often caused by measurement timing or a growth spurt. Talk with your pediatrician if the drop continues, crosses two major percentile lines, or comes with feeding problems or illness.
How often should I check my baby's percentile?
Most parents check at routine pediatrician visits — frequently in the first months, then at the 9, 12, 18 and 24 month check-ups. Checking occasionally at home is fine, but weighing and measuring every day usually adds worry rather than useful information.
Disclaimer: The results from this calculator are estimates for general information only and are not medical advice. Growth percentiles cannot diagnose any condition. Please consult your pediatrician about your baby's growth and health.