Reading growth results with perspective

What does a z-score describe?

A z-score describes distance from the reference centre for an indicator, age and sex. A value near zero is near that reference median; it is not an achievement score.

Respect each indicator's range

The tool supports height and BMI from 72 to 227 months. Weight-for-age is only shown up to 120 months, matching the relevant WHO reference range.

Check before drawing conclusions

Confirm age in months, units and measurement technique. If values fall outside plausibility checks or cause concern, remeasure and seek professional advice.

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.