Quick answer: Corrected age is your baby’s age counted from the due date instead of the birth date. Subtract the weeks born early from the actual age.
How do you calculate corrected age?
Corrected age = actual age − weeks born early.
- Find your baby’s actual age in weeks since birth.
- Work out how many weeks early they were born: 40 minus the weeks of pregnancy at birth.
- Subtract the weeks born early from the actual age.
Corrected age example
A baby born at 32 weeks was born 8 weeks early. At 24 weeks old, the corrected age is 24 − 8 = 16 weeks, about 3.7 months.
Corrected age chart
| Born at | Weeks early | Corrected age at 26 weeks old (6 months) |
|---|---|---|
| 36 weeks | 4 | 22 weeks (about 5.1 months) |
| 34 weeks | 6 | 20 weeks (about 4.6 months) |
| 32 weeks | 8 | 18 weeks (about 4.1 months) |
| 30 weeks | 10 | 16 weeks (about 3.7 months) |
| 28 weeks | 12 | 14 weeks (about 3.2 months) |
Who uses corrected age, and for how long?
Pediatricians commonly use corrected age for babies born before 37 weeks when they look at growth and milestones, usually until around age 2. Your baby’s doctor decides what suits your child.
Is corrected age used for vaccines?
Vaccines generally follow a baby’s actual age since birth, not the corrected age. Ask your pediatrician about your baby’s schedule.
Key takeaways
- Corrected age = actual age minus the weeks born early.
- It is mainly used for babies born before 37 weeks.
- Doctors usually stop using it around age 2.
- Try it in our baby age calculator with the “Born early?” option.
Frequently asked questions
When should you stop using corrected age?
Corrected age is most often used until around age 2, but your pediatrician decides what is right for your baby.
Is corrected age used for vaccines?
No. Vaccines generally follow the baby’s actual age since birth. Ask your pediatrician about your baby’s schedule.
Does corrected age apply to full-term babies?
No. Corrected age is usually not needed for babies born at 37 weeks or later.
Written by the Baby Age Calculator editorial team. Last updated October 28, 2026. General information only, not medical advice. See our medical disclaimer.