Babies born early: adjusted age
Work out your baby's corrected age from their birth date and due date.
The American Academy of Pediatrics says to adjust a baby's age for prematurity: take their age in weeks since birth and subtract the weeks they were born early. During the first 2 years, that corrected age gives a better idea of when your baby should reach common developmental goals. Enter both dates below.
Checked October 29, 2026.
How the AAP says to work it out
“Begin with your baby's actual age in weeks (number of weeks since the date of birth) and then subtract the number of weeks your baby was preterm.” To find the weeks preterm, the AAP says to subtract gestational age at birth from 40. Counting your baby's age from the due date gives the same answer, so this calculator does that.
The AAP's example: a baby born at 32 weeks was 8 weeks (2 months) early. At 4 months old (16 weeks since birth), her corrected age is 2 months, so you'd expect the skills of a 2-month-old.
Using it with the milestone pages
Look up your baby's corrected age on month by month. The CDC's Milestone Tracker app also adjusts for prematurity. If you're worried about your baby's development, talk with your pediatrician; they know your baby's history.
Privacy
Dates are worked out in your browser and not sent anywhere. If you tick “Remember”, they stay in this browser only.
Sources
- American Academy of Pediatrics (HealthyChildren.org), Corrected Age For Preemies (checked October 29, 2026)
- CDC, Milestone Tracker app (adjusts for prematurity) (checked October 29, 2026)