Adjusted Age Calculator
Updated
Quick answer: Adjusted age (also called corrected age) is your baby’s age minus the number of weeks they were born early. A 6-month-old who was born 8 weeks early has an adjusted age of about 4 months. Many families and doctors use adjusted age for sleep and development until around age 2.
Why adjusted age matters for sleep
Sleep patterns follow brain development, which tracks closer to a baby’s due date than their birth date. That’s why a premature baby’s naps and wake windows often match their adjusted age more closely than their actual age.
How to work it out
A full-term pregnancy is counted as 40 weeks. Subtract the number of weeks your baby was born early from their actual age. For example, a baby born at 34 weeks was 6 weeks early, so at 4 months old their adjusted age is about 2½ months.
When to stop using adjusted age
Many pediatricians use corrected age for developmental checks until about age 2. Ask your baby’s doctor or care team which age to use for your baby.
Common questions
Is corrected age the same as adjusted age?
Yes. Both terms mean a premature baby’s age counted from their due date instead of their birth date.
Should I use adjusted age for nap schedules?
Usually yes for babies born early. The calculator above saves your baby’s details so the nap calculator uses adjusted age automatically.
Does a baby born 2 weeks early need an adjusted age?
Babies born at 37 weeks or later are considered full term, so adjusted age makes little difference for them.