Child Growth Percentile Calculator

Shows where a child's height, weight and head circumference fall among children of the same age and sex, as a percentile and a z-score on growth curves. Use it to check a measurement again or to follow growth over time.

How to use

1. Choose the "Sex" and enter the "Date of birth" and "Date measured", or choose "Type age".
2. Enter any of "Height or length", "Weight" and "Head circumference", and choose the "Growth reference".
3. Read each percentile and z-score, and compare the point with the 3rd to 97th percentile curves on the chart.
4. Enter a "Nickname" and press "Save this measurement" to follow later measurements on the same curve; "Save as CSV" exports them.

How it works

• z = ((value ÷ M)^L − 1) ÷ (L × S), using the L, M and S values published for the WHO Child Growth Standards (2006, birth to 5 years), the Korea 2017 growth charts (0 to 18 years) and the US CDC 2000 growth charts (2 to 20 years). The z-score is then turned into a percentile.
• With "Use corrected age for a baby born early", age is counted from the due date until the second birthday. Saved records stay on this device.
• This calculator does not diagnose anything. Decisions about growth belong with a pediatrician, and the trend across several measurements matters more than one value.

Questions and answers

What does the 50th percentile for height mean?

Among 100 children of the same age and sex lined up by height, the child would be about number 50 from the shortest. The 50th percentile is the median.

Should a baby under 2 be measured lying down?

The references use length lying down under 2 years and standing height from 2 years. If measured the other way, set "How height was measured"; with WHO tables, 0.7 cm is added or subtracted.

Should I use the WHO or the CDC growth charts?

They cover different ages. The default on this page, WHO under 2 years and CDC from 2 years, follows the US CDC recommendation, and you can choose another reference.