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Premature infant corrected age

Calculate an educational corrected-age reference for a child born early. Enter completed pregnancy weeks and the extra days separately.

Start with your own numbers

Editable example

An example is filled in. Replace it with your own data to calculate.

For birth at 32 weeks 4 days, enter 32 weeks and 4 additional days.

Date of birthChoose date of birth using the date picker, or enter YYYY-MM-DD, for example 2026-11-03.

Completed gestational weeks at birthEnter completed gestational weeks at birth, for example 32. Use the displayed unit; replace the example with your own value.

Additional gestational daysEnter additional gestational days, for example 0. Use the displayed unit; replace the example with your own value.

Observation dateChoose observation date using the date picker, or enter YYYY-MM-DD, for example 2026-11-03.

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Example result

Corrected age

56days

Deducts the days born early to show corrected age. It does not change the birth date or diagnose development.

Actual age since birth112 days

Time born early56 days

Full corrected weeks8 weeks

Additional days beyond full weeks0 days

Corrected days = days since birth − (280 − gestational days at birth). Uses 40 weeks as the correction reference, which differs from the definition of full term. Before the estimated due date, shows days still remaining. Follows AAP guidance for educational reference during the first 2 years after birth; not a developmental diagnosis, vaccination schedule or medical decision tool.

Method and scope

Corrected days equal days since birth minus (280 minus gestational age in days at birth). The correction uses a 40-week baseline, which is different from the definition of full term.

Before the estimated due date, the result shows days still remaining rather than pretending the child has a positive corrected age. Chronological age still runs from actual birth.

This follows the AAP educational use during the first two years after birth. It does not diagnose development, set vaccination schedules or replace medical decisions.

References:American Academy of Pediatrics: Corrected Age for Preemies

What this helps you do

Calculate an educational corrected-age reference for a child born early. Enter completed pregnancy weeks and the extra days separately.

What to enter

Start with date of birth, then fill the other relevant fields in the units shown. The field hints explain the required format and examples.

How the calculation works

Corrected days equal days since birth minus (280 minus gestational age in days at birth). The correction uses a 40-week baseline, which is different from the definition of full term.

Worked example

A baby born at 32 weeks has an eight-week correction. At 12 weeks after birth, corrected age is about four weeks.

Understanding the answer

Before the estimated due date, the result shows days still remaining rather than pretending the child has a positive corrected age. Chronological age still runs from actual birth.

Scope and limitations