Weight-for-Length Calculator
Check how your baby's weight compares to other children of the same length and sex, using WHO growth standards. This is especially useful for children under 2 years who are measured lying down.
What is weight-for-length?
Weight-for-length looks at how your baby's weight relates to their length, rather than their age. This gives a clearer picture of body proportionality - whether your baby is lean, average, or heavy for their size.
Why it matters: Two babies can be the same age but very different lengths. A baby at the 25th percentile for weight-for-age might actually be perfectly proportional for their length. Weight-for-length helps tell the difference between a baby who is simply petite overall and one who may need nutritional support.
How it is measured: For children under 2 years, length is measured lying down (recumbent length). This is different from standing height, which is used for older children. The WHO provides separate reference charts for each.
This calculator uses WHO Child Growth Standards, the international reference recommended by the CDC for children under 2 years old.
Note: Based on WHO weight-for-length standards for children under 2 years. Data is for recumbent length (measured lying down), which is standard for this age group.
Disclaimer:This tool is for informational purposes only and does not replace professional medical advice. Growth percentiles are one piece of the puzzle - your pediatrician considers many factors when evaluating your baby's health. Always discuss any concerns with your child's healthcare provider.
All calculations happen in your browser. No data is stored or sent anywhere.