Child Weight Percentile Calculator (WHO 0–60 Months)
Enter your child's age (in months), sex, and weight to see where they fall on the WHO weight-for-age growth reference for 0–60 months. The calculator returns the percentile, z-score, and a distribution curve showing the result in context.
Sex
months
kg
Normal weight (15th–85th percentile)
- 1
WHO reference median & SD
μ = 12.18 kg, σ = 1.19 kgLinearly interpolated from WHO Multicentre Growth Reference Study (2006) for this age and sex. - 2
Z-score
(12 − 12.18) ÷ 1.19 = -0.15 - 3
Weight percentile
Φ(-0.15) × 100 = 44
How does this calculator work?
Enter age (0–60 months), sex, and weight; the calculator looks up the WHO 2006 reference median and SD, computes Z = (weight − median) / SD, and converts to a percentile via the standard normal CDF. Percentile 3–97 is typical; extremes need paediatric context.
Formula
How this is calculated
The WHO Multicentre Growth Reference Study (2006) provides sex-specific weight-for-age medians and standard deviations from birth to 60 months, derived from children raised in optimal health conditions across six countries. This calculator interpolates those reference values for the child's exact age in months, then computes a Z-score: how many standard deviations the child's weight is above or below the WHO median.
The Z-score is converted to a percentile using the standard normal cumulative distribution function. A child at the 50th percentile weighs exactly the WHO median for their age and sex; a child at the 3rd percentile is lighter than 97% of the reference population. Percentiles below 3 or above 97 may warrant monitoring but must be interpreted in the context of the child's overall growth trajectory, family history, and diet — a single measurement is far less informative than a trend over time.
This calculator uses a simplified normal approximation. True WHO growth charts use the LMS (Box-Cox power) method to handle slight skewness in weight distributions, so results may differ by 1–3 percentile points at the extremes. For clinical use, consult the official WHO charts or a paediatrician.
Frequently asked questions
The 15th–85th percentile range is generally considered normal. However, a healthy percentile for any individual child depends on their growth trend over time, height, ethnicity, and genetics — a consistent 5th percentile in an otherwise thriving child may be perfectly normal, while a drop from the 60th to the 20th in a few months warrants evaluation.
This tool uses the WHO Multicentre Growth Reference (2006), which covers birth to 60 months. For children aged 5–19 years, the WHO 2007 reference or the US CDC 2000 growth charts are typically used — those involve height-adjusted measures (BMI-for-age) which are a separate calculator.
Results are approximate. The true WHO method uses a Box-Cox transformation (LMS parameters) to account for the slight right-skew in weight distributions. This calculator assumes a normal distribution and linearly interpolates between reference points, which may introduce errors of 1–3 percentile points at the extremes (< 5th or > 95th percentile).
Also known as
TG we-Calculate Editorial Team. (2026). Child Weight Percentile Calculator (WHO 0–60 Months) [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/child-weight-percentile-calculator
TG we-Calculate Editorial Team. "Child Weight Percentile Calculator (WHO 0–60 Months)." TG we-Calculate. 2026. https://we-calculate.com/calculator/child-weight-percentile-calculator.
TG we-Calculate Editorial Team, "Child Weight Percentile Calculator (WHO 0–60 Months)," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/child-weight-percentile-calculator
@misc{wecalculate_child_weight_percentile_calculator, title = {Child Weight Percentile Calculator (WHO 0–60 Months)}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/child-weight-percentile-calculator}}, year = {2026}, note = {TG we-Calculate} }
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