Free tool
Corrected age calculator
For babies born early, corrected (adjusted) age is measured from the due date — a fairer way to follow development. Enter a birth date and gestational age to see it instantly.
Enter a birth date and gestational age to see the corrected age.
Corrected (adjusted) age counts from the estimated due date, so a preemie’s development is compared fairly. It’s a gentle guide, not medical advice — your care team knows your baby best.
Frequently asked questions
What is corrected age?
Corrected age (also called adjusted age) is your baby’s age counted from their estimated due date instead of their birth date. It reflects how developed your baby would be if they had been born on time.
How do you calculate corrected age?
Take the chronological age (time since birth) and subtract the number of weeks your baby was born early. This calculator does it instantly from the birth date and gestational age.
Until what age should I correct?
Most clinicians correct age until about 2 years, by which time many preterm babies have caught up. Your care team will advise what’s right for your child.
Is this a medical tool?
No. It’s a free, educational calculator to help you understand corrected age. It isn’t medical advice — your baby’s care team knows them best.