What is corrected age, and why it matters for preemies
If your baby arrived early, you’ll often hear two different ages: chronological age and corrected age. Understanding the difference takes a lot of worry out of those early months.
Chronological vs. corrected age
Chronological age is simply the time since birth. Corrected age (also called adjusted age) is counted from the estimated due date — so it reflects how far along your baby would be if they had arrived on time.
For example, a baby born 8 weeks early who is 3 months old chronologically has a corrected age of about 1 month.
Why it matters
- Developmental milestones are compared against corrected age, not birth date.
- Growth charts for preterm babies are plotted on corrected age.
- It helps set realistic, kind expectations — your baby isn’t “behind”, they’re on their own timeline.
How long do you correct for?
Most clinicians correct age until around 2 years, by which point many preterm babies have caught up. Your care team will guide you on what’s right for your child.
You can work out your baby’s corrected age any time with our free corrected-age calculator — no sign-up needed.
Want this on corrected age automatically? Try the calculator or get the app.