Corrected Age Calculator
Find a premature baby's corrected age for milestones, growth and feeding.
Corrected age calculator
For babies born before 37 weeks: subtract the weeks born early to see their age for milestones and growth.
Quick answer
Corrected age is a premature baby's actual age minus the number of weeks they were born early (40 weeks minus weeks of pregnancy at birth). A 6-month-old born at 32 weeks has a corrected age of about 4 months. Use it until about age 2.
How corrected age is calculated
Subtract the weeks of pregnancy at birth from 40 to get the weeks born early, then subtract that from the baby's actual age. The calculator does this to the day.
Doctors use corrected age to judge development and growth because a premature baby has had less time to develop. Vaccines are the exception: they are given by actual age.
Weeks born early
Weeks early = 40 − weeks of pregnancy at birth.
| Born at | Weeks early | At 6 months actual age, corrected age is about |
|---|---|---|
| 28 weeks | 12 | 3.2 months |
| 30 weeks | 10 | 3.7 months |
| 32 weeks | 8 | 4.2 months |
| 34 weeks | 6 | 4.6 months |
| 36 weeks | 4 | 5.1 months |
Frequently asked questions
Until what age should I use corrected age?
Usually until about 2 years, when most premature babies have caught up. Your doctor may stop earlier.
Do vaccines follow corrected age?
No. Vaccines are given by actual (chronological) age, even for premature babies.
Should I start solids by corrected age?
Generally yes — most premature babies are ready for solids at around 6 months corrected age. Ask your baby's doctor.
What counts as premature?
Born before 37 weeks of pregnancy.
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