Use this height percentile calculator to see how your baby’s length compares with babies of the same age and sex, using WHO growth standards for ages 0–24 months. Enter your baby’s sex, age and height (length) below and you will get their height percentile instantly, with a plain-English explanation of what it means.
Height Percentile Calculator
Length vs height: what is the difference?
Babies under 24 months are usually measured lying down, and that measurement is called length. Older children are measured standing up, which is called height. Length and height describe the same thing — how long or tall your baby is — and a lying-down measurement can be slightly longer than a standing one. This calculator uses the WHO length-for-age standards for babies aged 0–24 months.
How to use this calculator
- Step 1: Choose your baby's sex and enter their age in months (0–24).
- Step 2: Enter their length or height, and choose cm or inches.
- Step 3: Tap Calculate Percentile to see the height percentile and what it means in plain English.
More baby tools and guides
Find your baby's exact age with our baby age calculator, see weight and length together in the baby percentile calculator, and follow overall growth on the baby growth chart page.
Frequently asked questions
How is height percentile calculated?
Your baby's length is compared with WHO growth-standard reference values for babies of the same age and sex. The calculator works out a z-score from the difference between your baby's length and the median length, then converts that score into a percentile.
What height percentile is normal for a baby?
A wide range is normal. Most babies fall between the 3rd and 97th percentiles, and a lower or higher percentile is not better or worse by itself. Steady growth along a curve over time matters more than any single number.
Does height percentile predict adult height?
Only loosely. A baby's percentile gives a rough idea of growth pattern, but genetics matters most for adult height, along with nutrition and overall health. Many babies change percentiles in the first two years before settling near their family pattern.
When should I be concerned about my baby's length?
Talk with your pediatrician if your baby's length crosses two major percentile lines, stays below the 3rd or above the 97th percentile, or growth seems to slow or stop. Your doctor can check growth in full context.
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.