Baby Weight Percentile Calculator
Enter your baby's age, sex, and weight to instantly see their weight-for-age percentile, plotted on an interactive WHO or CDC chart.
Infant Growth Percentile Calculator.
Enter your baby's measurements and location to see percentiles on the most appropriate growth chart for your region — with interactive curves, growth spurt indicators, and a printable report.
Weight-for-age
Height-for-age
What do these numbers mean?
Multi-child dashboard.
No saved measurements yet
Calculate your baby's percentiles above, then click "Save to Dashboard" to track growth over time.
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Understanding weight-for-age percentile
Weight-for-age is one of the most commonly tracked infant growth metrics at well-child visits. It compares your baby's weight to a reference population of the same age and sex — a 40th percentile means 40% of same-age, same-sex babies weigh less, and 60% weigh more.
Weight-for-age is most informative when tracked over multiple visits rather than as a single snapshot, since it shows whether your baby is gaining weight at a rate consistent with their own growth curve.
Typical weight gain by age
Newborns typically regain their birth weight by 2 weeks, then gain roughly 5–7 oz per week through 4 months, slowing to 3–5 oz per week from 4–6 months, and further slowing through the first year. Most babies double their birth weight by around 5 months and triple it by 1 year.