American Academy of Pediatrics (AAP) Corrected Age Standard

Adjusted Age Calculator for Preterm Infants

Calculate corrected gestational age for premature infants born prior to 37 weeks. Essential for developmental milestone tracking, growth charts, and early intervention programs up to 24 months of age.

Corrected / Adjusted Developmental Age
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Chronological Age: --
Clinical Notation: --
Actual Days Since Birth
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Total Weeks Elapsed
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AAP Milestone Rule
Use Corrected Age
Next Birthday
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Pediatric Assessment Slip

          

        


      


      

      
      

        

          
What is the Difference Between Chronological Age and Corrected Age?

          

            When a baby is born early, they have two different ages:
          

          
    
            
  • Chronological Age: The actual amount of calendar time that has passed since birth day (birthday age).
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  • Adjusted / Corrected Age: The chronological age minus the number of weeks the baby was born prematurely. This represents the age the child would be if they had been born on their due date (40 weeks gestation).
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Why the American Academy of Pediatrics (AAP) Uses Corrected Age

          

            A full-term human pregnancy lasts 40 weeks. A baby born at 30 weeks gestation missed 10 weeks of critical in-utero brain, lung, and physical development. When evaluating milestones such as rolling over, sitting up, crawling, or speech:
          

          

            The 2-Year Milestone Rule:
            Developmental pediatricians and early childhood intervention specialists always benchmark a preterm child's motor, cognitive, and social milestones against their Adjusted Age until the child reaches 24 months (2 years) of age, after which catch-up growth typically aligns their development with their chronological peers.