Preterm Babies & Corrected Age
A baby born at 32 weeks is biologically 8 weeks younger than a baby born at term on the same calendar day. Corrected age accounts for that gap, and using it correctly prevents under- and over-identification of developmental concerns during the first two years.
Last reviewed: June 25, 2026
Calculators in this topic
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Calculate adjusted (corrected) age for babies born preterm. Used to interpret growth, milestones, and screening tools accurately until 24 months.
Convert your baby's date of birth to exact age in years, months, weeks, and days. Perfect for milestones, vaccinations, and pediatric visits.
Plot your baby's weight and length against WHO Child Growth Standards. Get percentiles and z-scores instantly.
Score the Ages & Stages Questionnaire (ASQ-3) instantly across all five domains. Free, accurate, and aligned with official cutoffs.
Formula and clinical use
Corrected age = chronological age − (40 weeks − gestational age at birth). Use it for growth percentiles, ASQ-3, and feeding milestones through at least 24 months. After age 2, most clinicians transition back to chronological age.
Growth and feeding implications
Preterm growth charts (Fenton, then WHO at term-corrected) are used until 50 weeks postmenstrual age. After that, plot against WHO charts using corrected age.
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