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Child Growth Percentile Calculator

Estimate weight-for-age and length/height-for-age percentiles for children from birth through 5 years using bundled WHO LMS reference anchors.

Use this result well

Inputs that matter
Child age from birth through 60 completed months, WHO boy/girl reference, weight, and recumbent length or standing height in metric or imperial units
Output to expect
Approximate WHO weight-for-age and length/height-for-age z-scores, percentiles, and reference-line context
How it works
Sex-specific bundled WHO LMS anchors with linear age interpolation, LMS z-score calculation, and standard-normal percentile conversion
  • Use recumbent length under age 2 and standing height from age 2; measurement technique and exact age can shift the estimate.
  • A single percentile is not a diagnosis. Pediatric interpretation depends on accurate serial measurements, the appropriate chart, history, and professional assessment.

Choose your path

Built around the job you need to finish

Estimate WHO weight-for-age and length/height-for-age context for birth through 60 months without presenting a sparse reference or one measurement as a diagnosis.

Caregiver checking one measurement

Place weight and length/height in age- and sex-specific WHO context.

Enter completed years/months, choose the WHO boy/girl reference, and enter both measurements.

Receives finite z-score/percentile estimates and understands they are a screen.

Caregiver measuring at home

Avoid mixing recumbent length and standing height.

Review the measurement note before entering length under 2 or standing height from age 2.

Repeats the measurement consistently and seeks professional confirmation for surprising results.

Pediatric professional or informed reviewer

Know the reference resolution and age boundary.

Review the WHO-only 0–60 month and bundled-anchor interpolation disclosure.

Does not infer official chart precision, CDC coverage, diagnosis, or trend from one result.

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Reference & details

How it works

WHO Growth Standards

WHO child growth standards cover ages 0–5. This browser tool uses bundled sex-specific weight-for-age and length/height-for-age LMS anchors and linearly interpolates between available ages.

WHO LMS z-score → standard-normal percentile

Source: WHO Child Growth Standards

Z-Score Conversion

The LMS method accounts for age-specific skewness (L), median (M), and variation (S). The resulting z-score is converted to an approximate standard-normal percentile.

Z = ((measurement / M)^L − 1) / (L × S); logarithmic form when L ≈ 0

Scope and measurement method

Use recumbent length under age 2 and standing height from age 2. A single estimate is not diagnostic; clinicians interpret accurate serial measurements, health history, and the appropriate chart together.

Supported age = 0–60 completed months

Updated: August 2026

Example Scenarios

A pediatric visit tracks whether a toddler's height and weight fall within expected growth ranges.

Age: 18 monthsHeight: 82 cmWeight: 11.5 kgSex: Boy

Two WHO-based screening estimates; verify the measurements and follow the child's trend over time

A caregiver records a measurement for discussion with a pediatric professional, paying attention to the child's serial growth pattern rather than diagnosing from one percentile.

Age: 3 yearsHeight: 90 cmSex: Girl

An approximate WHO percentile and z-score, with a prompt to seek professional interpretation of unusual or changing patterns

A caregiver compares recumbent length versus standing-height instructions before entering the value, because mixing methods can shift the estimate.

Common Mistakes to Avoid

Panicking over a single percentile reading

Growth is tracked over time, not single measurements. A child at the 15th percentile is normal if following their curve. Concern arises when percentiles cross downward significantly.

Using adult BMI standards for children

Pediatric growth uses age- and sex-specific percentile charts (WHO/CDC). Adult BMI categories do not apply. Always use pediatric reference charts.

FAQ

It is an approximate screen based on bundled WHO LMS anchors and linear interpolation. Input technique, exact age, reference resolution, and clinical context matter; use a professional chart and serial measurements for medical decisions.

Yes, our Child Growth Percentile Calculator is completely free with no registration required. There are no usage limits, hidden fees, or account setup — just open the tool and calculate.

Yes, the Child Growth Percentile Calculator is fully responsive and works on all devices including phones, tablets, and desktops. All calculations run in your browser for fast, private results.

Use recumbent length for children under 2 and standing height from age 2. Keep the method consistent over time and ask a pediatric professional to confirm technique when a result is surprising.

The calculation runs in the browser, but avoid entering names or other identifiers and remember that browser/device behavior can vary. The tool does not need a child's identity to estimate a percentile.

About Child Growth Percentile Calculator

Enter a child's completed age, sex reference, weight, and recumbent length or standing height for a WHO-based screening estimate from birth through 5 years. The bundled reference is interpolated and the result cannot diagnose growth or replace a pediatric growth chart review.