Fenton 2013 growth calculator for preterm infants
Prepare postmenstrual age and measurement inputs for the Fenton 2013 preterm growth chart. This page checks the age workflow, flags the chart range, and packages values for exact percentile and z-score calculation in PediTools or local chart software.
Last reviewed: 2026-04-28
Percentile handoff
What this page calculates
The calculator converts the entered weeks and days into a clean postmenstrual age label, checks whether the value falls inside the Fenton 2013 monitoring range, and formats the anthropometric inputs for the official percentile workflow.
- Use postmenstrual age at the measurement date, written as weeks plus days.
- Enter weight in grams, head circumference in centimeters, and length in centimeters.
- Copy the entry package into PediTools or the chart software your team uses for final z-score output.
When Fenton 2013 is still useful
Many NICU records, research datasets, and follow-up clinic protocols still reference the second-generation Fenton 2013 charts. Use this route when you need a 2013-specific input workflow or need to reconcile an older percentile report with current measurements.
If your institution has moved to the third-generation charts, use the newer Fenton 2025 workflow and document the version used so future growth trends are interpreted against the same chart family.
Official percentile tools
Preterm growth workflow
- Confirm gestational age at birth and current postmenstrual age.
- Repeat any unexpected weight, length, or head circumference measurement.
- Calculate percentile and z-score in the official Fenton 2013 tool.
- Compare the current z-score with prior Fenton 2013 values when available.
- Document the chart version before transitioning to WHO or local term charts.
Related calculators
References
FAQs
No. It prepares sex, postmenstrual age, weight, head circumference, and length so you can enter them cleanly into PediTools or another official Fenton 2013 chart workflow for exact percentile and z-score output.
Exact Fenton 2013 percentiles depend on the chart data and calculation engine. This page avoids maintaining a separate copy of the LMS tables and instead focuses on the input and documentation workflow.
The 2013 Fenton and Kim paper describes preserving preterm chart data integrity from 22 to 36 weeks and smoothing to 50 weeks postmenstrual age. Use local protocol for transition timing.
Use the chart family required by your NICU, EHR, research protocol, or follow-up clinic. Fenton 2025 is the newer generation, while many existing workflows and historical reports still reference Fenton 2013.
Document the chart version, sex, postmenstrual age, measured weight, length, head circumference, percentile or z-score, and how the trend compares with prior values.