Child Growth Percentile Calculator (LMS Approximation)
Approximate weight-for-age percentile for children.
Enter your values
ⓘ Live results
Results
- Weight-for-age z-score
- -0.42
- Approximate percentile
- 33.8th
- Reference median weight
- 12.9 kg
Quick answer
Growth percentile compares a child's weight to a reference population of the same age and sex using a z-score.
z = (weight - median) / SD; percentile from standard normal distribution
How to use the Child Growth Percentile Calculator (LMS Approximation)
- 1Enter the child's sex, age in months and current weight.
- 2This uses a simplified reference curve for illustration and general tracking, not official WHO/CDC LMS tables.
- 3For clinical growth monitoring, use your pediatrician's official growth chart, since exact percentiles need age-specific LMS parameters.
Worked example
Using the values the calculator loads with:
Inputs
- SexBoy
- Age24 months
- Weight12.2 kg
Results
- Weight-for-age z-score-0.42
- Approximate percentile33.8th
- Reference median weight12.9 kg
Frequently asked questions
Why isn't this exact?
Official growth charts use detailed LMS parameters per month of age; this tool approximates the trend.
What if my child is below the 5th percentile?
Discuss with a pediatrician — it can be normal for that child, or a sign to investigate further.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.