What this result means
The calculator compares weight, length or height, and head circumference with WHO sex-specific LMS standards for completed months from birth through five years.
WHO Child Growth Percentile Calculator (Birth to 5 Years)
WHO growth comparison
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Reference range
How this result is calculated
A clear calculation path based on your inputs.
Inputs usedReview the information used for this result.
Full calculation and sourcesWHO monthly LMS tables convert each measurement to a z score; the normal cumulative distribution provides an approximate percentile position.
Versioned calculationFormula v1.0.0
Method used
WHO monthly LMS tables convert each measurement to a z score; the normal cumulative distribution provides an approximate percentile position.
Important boundary
Percentiles are screening comparisons. A clinician should interpret unexpected change, extreme measurements or growth concerns.
Enter the evidenceUse current measurements, dates, label details or report values.
Apply the bounded methodWHO monthly LMS tables convert each measurement to a z score; the normal cumulative distribution provides an approximate percentile position.
Read the full resultUse the primary result together with the supporting outputs and limitations.
Choose the next actionPercentiles are screening comparisons. A clinician should interpret unexpected change, extreme measurements or growth concerns.
Interpretation
At an exact WHO monthly median, the z score is 0 and the approximate percentile position is 50.
WHO monthly LMS tables convert each measurement to a z score; the normal cumulative distribution provides an approximate percentile position.
Percentiles are screening comparisons. A clinician should interpret unexpected change, extreme measurements or growth concerns.
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Child and Teen BMI Percentile CalculatorUse CDC BMI-for-age from age two through 19.Baby Age CalculatorCalculate completed calendar age for the measurement date.Corrected Age CalculatorReview corrected age for a baby born early.India Vaccination Schedule Date PlannerMap national schedule milestones from date of birth.
Method and test recordFormula v1.0.0
- Recorded scope
- WHO Child Growth Percentile Calculator (Birth to 5 Years) inputs, method, boundary behavior, result presentation and source mapping.
- Publisher
- CalculatorGeek
- Recorded review date
- 2026-10-11
- Next source review
- 2027-01-11
- Definition fixtures
- 2 configured scenarios
- Published examples
- 2 shown below
Recorded method
Primary-source reconciliation, deterministic normal/boundary/invalid fixtures, JavaScript/PHP parity and responsive rendered-page QA.
These records describe the published model and reference tests. A test-case count is not a certification of every possible input or an independent specialist review. Editorial policy
Known limitations
- No diagnosis or individualized growth target is produced.
- Age is handled in completed whole months.
- Weight-for-length and BMI-for-age are outside this route.
Method sources
- WHO Child Growth Standards - standards overview
- WHO Child Growth Standards - weight for age
- WHO Child Growth Standards - length or height for age
- WHO Child Growth Standards - head circumference for age
Latest model update
2026-10-11 - Initial shared-system implementation with primary-source method mapping, original content and contextual links.
Reference inputs and expected results
Up to 12 examples from the configured definition fixtures are shown. Expected values use the stated output units; invalid inputs are intended to be rejected.
| Case | Inputs | Expected result |
|---|---|---|
| WHO girls table at 24-month medians | WHO growth reference table: female; Completed age in months: 24 months; Measured weight: 11.4775 kg; Measured length or height: 85.7153 cm; Measured head circumference: 47.1822 cm; Length or height measurement method: standing_height | Weight-for-age z score: 0 z; Weight-for-age percentile band position: 50.0000000525 %; Length or height-for-age z score: 0 z; Length or height-for-age percentile band position: 50.0000000525 %; Head-circumference-for-age z score: 0 z; Head-circumference-for-age percentile band position: 50.0000000525 %; Measurement-method adjustment: 0 cm (allowed numeric tolerance: 1.0E-6) |
| Reject age after five years | WHO growth reference table: female; Completed age in months: 61 months; Measured weight: 18 kg; Measured length or height: 110 cm; Measured head circumference: 50 cm; Length or height measurement method: standing_height | Reject invalid input: validation error |
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On this page
Compare three measurements with WHO monthly standards
The calculator compares weight, length or height, and head circumference with WHO sex-specific LMS standards for completed months from birth through five years.
A percentile is a comparison position, not a diagnosis or target. Growth over time, measurement technique, gestational history and the clinical context matter more than one isolated point.
For a connected task, continue with Child and Teen BMI Percentile Calculator, Baby Age Calculator, Corrected Age Calculator, India Vaccination Schedule Date Planner.
How to use the WHO Child Growth Percentile Calculator (Birth to 5 Years)
- Choose the WHO girls or boys reference table.
- Enter completed age in whole months.
- Enter measurements taken on the same date.
- Identify whether stature was measured lying down or standing.
- Calculate and compare the three z scores without averaging them into one growth grade.
For a child born early, discuss corrected age with the child’s clinician before interpreting early measurements.
Method and calculation
The WHO LMS method uses age-specific L, M and S values. For nonzero L, z = ((measurement / M)^L - 1) / (L × S); when L is zero, the logarithmic form is used. A normal cumulative distribution converts z to an approximate percentile position.
WHO expects recumbent length below 24 months and standing height from 24 months. When the other method is entered, this implementation adds 0.7 cm to standing height below 24 months or subtracts 0.7 cm from recumbent length at 24 months and older.
Worked example
A 24-month-old child entered at the matching WHO median values produces z scores near 0 and percentile positions near 50 for weight, standing height and head circumference. A z score near 0 means close to the reference median; it does not say that every healthy child should follow the 50th percentile.
Inputs, outputs and result meaning
The shared CalculatorGeek renderer keeps entered values, calculated results, copied text, printed output and reset behavior in one workflow. The inputs are:
- WHO growth reference table: Choose the sex-specific WHO standard used by the source tables.
- Completed age in months: Use completed whole months from birth through 60 months.
- Measured weight: Use a current measurement without clothing when practical.
- Measured length or height: Enter the observed value before any method adjustment.
- Measured head circumference: Measure around the broadest part of the head with a non-stretch tape.
- Length or height measurement method: WHO expects recumbent length under 24 months and standing height from 24 months.
The result contract is:
- Weight-for-age percentile band position: Approximate normal-distribution position derived from the WHO LMS weight-for-age z score.
- Weight-for-age z score: Standard-deviation position relative to the sex- and age-specific WHO median.
- Length or height-for-age percentile band position: Approximate position for normalized length or height.
- Length or height-for-age z score: WHO LMS z score for normalized length or height.
- Head-circumference-for-age percentile band position: Approximate position for head circumference.
- Head-circumference-for-age z score: WHO LMS z score for head circumference.
- Length or height used by model: Entered stature after the WHO 0.7 cm cross-method adjustment when needed.
- Measurement-method adjustment: Zero when the expected method is used, otherwise plus or minus 0.7 cm.
Changing any input makes the previous answer stale until the calculation is run again. Units remain attached to their values, and display rounding does not change the underlying calculation.
Interpretation, safety boundaries and limitations
This tool does not assess weight-for-length, BMI-for-age, prematurity, syndromes, nutritional status or the reason a growth path changed. Percentiles near the extremes are especially sensitive to measurement error. Repeated measurements should use consistent technique and be plotted over time. Contact a pediatric clinician for rapid crossing of major bands, feeding concern, developmental concern or an implausible result.
Frequently asked questions
Is the 50th percentile ideal?
No. It is the reference median, not a health target.
Why can standing and lying measurements differ?
Recumbent length is typically about 0.7 cm greater, so WHO supplies a cross-method adjustment.
Does one low percentile diagnose poor growth?
No. Trend, measurement quality and clinical context are required.
Can I use this after age five?
No. This route is intentionally limited to WHO birth-to-five standards.
Sources and evidence
These sources define the method or its safety boundary. CalculatorGeek does not treat a competitor page, marketing claim or search snippet as clinical evidence.
Evidence