Premature Baby Adjusted Age Calculator: How to Calculate Corrected Age

For premature infants, many early intervention and developmental assessments use adjusted (corrected) age—age from the due date, not the birth date—until the child is about 2 years old. Our chronological age calculator can give you adjusted age: enter the due date as the start date and the assessment date as the end date.

Why Use Adjusted Age for Preemies

Adjusted age accounts for weeks of prematurity so developmental expectations and screening results are compared to the correct reference. Protocols (e.g., ASQ, Bayley) often specify when to use chronological vs adjusted age.

How to Get Corrected Age in Our Calculator

In the calculator: set Start Date (Birth Date) to the baby's due date, and End Date to the assessment or screening date. The result is the adjusted age in years, months, and days. For chronological age, use actual birth date as start date.

Free premature adjusted age calculator (use due date as start)