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Baby Growth Percentile Calculator

Estimate your baby's weight percentile compared to WHO growth references.

How this is calculated
z-score = (weight − reference median) ÷ reference SD, converted to a percentile via the normal distribution

Assumptions used in this calculation

  • Simplified reference: Interpolates between a reduced set of WHO checkpoints (0, 3, 6, 9, 12, 18, 24 months) rather than using the full LMS growth curve.

About this calculator

The baby growth percentile calculator estimates a weight-for-age percentile using a simplified, interpolated version of WHO growth reference points (0-24 months), for boys and girls separately.

Worked example

Boy, 12 months, 9.6 kg

Result: ≈ 50th percentile (at the reference median)

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