Calculate your baby's corrected age

Corrected age, also called adjusted age, accounts for the weeks a baby was born before their due date. A baby born eight weeks early has a corrected age eight weeks behind their actual age. It helps put growth and development in context.

Take your baby’s age today and subtract how early they arrived. If your baby is 5 months old and was born 2 months before their due date, their corrected age is 3 months. If you know the gestational age at birth instead, the weeks early are simply 40 minus the weeks your baby was born at: a baby born at 32 weeks was 8 weeks early.

Correction usually stops around age 2, sometimes 3 for babies born very early. Check with your pediatrician about which age to use for your baby.

Corrected age can help interpret growth and developmental milestones. It does not predict the date a skill will appear. Vaccines generally follow actual age rather than corrected age. Ask your care team about your baby’s vaccine schedule and about readiness for solids.

A baby born before 37 weeks of pregnancy is premature. Within that, birth at 34–36 weeks is late preterm, 32–33 weeks is moderately preterm, 28–31 weeks is very preterm, and before 28 weeks is extremely preterm. The earlier the birth, the longer corrected age tends to stay useful.

Yes. Enter the gestational age at birth in Plumi’s baby growth tracker and it measures from the due date on WHO percentile charts automatically, phasing correction out by age two. Our guide to the wide range for crawling shows how corrected age can put a milestone into context.