Dr. BabyA little guide · Growth
Baby growth
percentiles explained.
A percentile is a comparison with a reference group. Move the slider to see what the number means.
50th percentile
An illustration of ranking, not a chart of individual babies or a medical assessment.
The 50th percentile is not a goal.
If a weight measurement is at the 25th percentile, roughly 25 out of 100 babies in the same-age, same-sex reference group weigh less, and roughly 75 weigh more. That number alone does not tell you whether a baby is healthy.
Growth is a story told over time.
Your pediatrician considers repeated measurements, length, health history and other context. A weight-for-age percentile does not assess weight relative to length. Measurements can also vary with equipment and technique.
Which reference does the web calculator use?
The Dr. Baby web calculator uses WHO weight-for-age reference data for birth to 24 months. CDC recommends WHO growth standards for children under age 2 in the United States.
Sources: WHO growth standards ↗ · CDC guidance ↗
Try the weight calculatorA useful place to start
How to use this tool
Move the slider to compare different positions in a reference group of 100. The illustration explains ranking without assigning a health score.
Back to the interactive tool ↑How Dr. Baby’s web tools are made
These are educational tools from Dr. Baby. The name does not mean that a clinician has reviewed this website. The weight tool uses the WHO daily weight-for-age reference tables; its inputs, calculation and limits are explained on the calculator page. The corrected-age method links to AAP guidance. The sleep planner explicitly lists its sample assumptions.
Generated results are calculations or summaries of your entries, not diagnoses. Source links let you check the underlying information. The web tools and the upcoming mobile app are separate products; this website does not promise that saved web entries will transfer to the app.
Content updated · Methods, sources & limitations