Adjusted Age Calculator
Find the corrected age of a baby born early, from the birth date and the weeks of gestation at birth.
Corrected age
11.1 weeks
- Corrected age in months
- 2 months
- Weeks born early
- 8 weeks
- Actual age in weeks
- 19.1 weeks
- Actual age in months
- 4 months
Born 8 weeks early, at 32 weeks, this baby's corrected age is 11.1 weeks, or about 2 months. Corrected age is usually used for development during the first 2 years.
Calculation breakdown
| Step | Formula | Result |
|---|---|---|
| Weeks born early | 40 − 32 weeks | 8 weeks |
| Actual age | 134 days ÷ 7 | 19.1 weeks |
| Corrected age | 19.1 weeks − 8 weeks | 11.1 weeks |
How it works
Enter the date of birth, the weeks of pregnancy at birth, and the date you want the age on, which starts as today.
Worked example
A baby born at 32 weeks, now 16 weeks old:
- Weeks born early: 40 − 32 = 8 weeks
- Corrected age: 16 − 8 = 8 weeks, which is about 2 months
Rounding
Weeks are shown to one decimal place. Months count whole calendar months from the original due date.
Sources
Frequently asked questions
What is adjusted or corrected age?
It is a baby's age counted from the original due date instead of the birth date. The American Academy of Pediatrics' HealthyChildren.org says corrected age gives a better idea of when to expect common developmental milestones for a baby born early.
How do you calculate corrected age?
Subtract the gestational age at birth from 40 to find the weeks born early, then subtract that number from the baby's actual age in weeks. A baby born at 32 weeks is 8 weeks early, so at 16 weeks old her corrected age is 8 weeks, about 2 months.
How long should I use corrected age?
HealthyChildren.org says corrected age is useful during the first 2 years. Ask your child's pediatrician how to use it for your child, since doctors may adjust their advice for each baby.
What if my baby was born at 39 weeks?
HealthyChildren.org says a pregnancy is now considered full term at 39 weeks, but the corrected age formula still subtracts from 40, so this calculator shows a 39-week baby as 1 week early. Ask your pediatrician whether to correct for a baby born at 39 weeks.
Should I use corrected age for medical decisions?
Use this calculator as an information tool only. Your child's doctor decides how to use corrected age for growth, development and any medical care, so follow their advice.
For information only, not medical advice. Ask your child's pediatrician how to interpret growth and development for your baby.