How is a reference row selected?
Completed age is converted to months, and the table's sex category selects the reference row. This implementation does not extrapolate outside months 72–227.
What do L, M and S do?
The parameters describe distribution shape, median and spread. Calculation follows WHO methodology, including its extended-tail treatment for BMI and weight.
Scope of verification
The tool’s first and last supported rows were compared with public WHO tables, and monthly coverage was checked. This is representative verification, not clinical validation.
References
- WHO — Height-for-age (5–19 years)
- WHO — BMI-for-age (5–19 years)
- WHO — Weight-for-age (5–10 years)
- WHO — Computation of centiles and z-scores
Reviewed on 3 October 2026. These sources do not endorse or certify Siroby.