Weight Percentile For Children Calculator

Work out weight percentile for children instantly with clear inputs, formula shown and shareable results.

About Weight Percentile For Children Calculator

The weight is turned into a z-score against the published mean and standard deviation for the child's age and sex, and the normal curve converts that into a centile. A single weight means little on its own; the centile places it against a reference population, and repeated centiles show whether growth is tracking.

Formulas

Z-score

z = (weight - reference mean) / reference standard deviation

Centile

centile = normal cumulative distribution of z x 100

Worked example

With the default values below, Weight Percentile For Children Calculator returns Weight percentile of 63.1%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Child's weightminimum 1 kg: 22 kg
Reference mean weight for ageminimum 1 kg: 21 kg
Reference standard deviationminimum 0.1 kg: 3 kg

Results

Weight percentile: 63.1%
Z-score against the reference: 0.333
Difference from the reference mean: 1.00 kg
Interpretation: Within the typical range

Step by step

1Values used
2Z-score
3Centile
4Weight percentile= 63.1
5Z-score against the reference= 0.333
6Difference from the reference mean= 1.00 kg
7Interpretation= Within the typical range

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Weight Percentile For Children figure worked out?

z = (weight - reference mean) / reference standard deviation. The weight is turned into a z-score against the published mean and standard deviation for the child's age and sex, and the normal curve converts that into a centile.

Why does this matter?

A single weight means little on its own; the centile places it against a reference population, and repeated centiles show whether growth is tracking.

What do I need to enter?

Enter child's weight, reference mean weight for age, reference standard deviation. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.