Adjusted Age Calculator
The Adjusted Age Calculator estimates a baby’s corrected developmental age based on their birth date, due date, and gestational age. This tool helps parents and pediatricians track growth milestones more accurately than using chronological age alone. Whether you are assessing motor skills, planning for school readiness, or monitoring weight gain, this calculator provides clarity. By understanding adjusted age, you can better support your child’s specific needs during critical early years.
How Adjusted Age Is Calculated
Adjusted age, often called corrected age, measures a premature baby's development based on their due date rather than their birth date. This calculation helps you understand how your child compares to full-term peers. The standard method accounts for the time missed in the womb.
Adjusted Age = Chronological Age – (40 – Gestational Age at Birth)
Where:
- Chronological Age = Time elapsed since actual birth
- Gestational Age at Birth = Weeks of pregnancy at delivery
- 40 = Full-term gestation in weeks
- Calculate the baby's chronological age by finding the time passed between the Birth Date and Current Date.
- Determine how many weeks early the baby was born by subtracting the Gestational Age at Birth from 40 weeks.
- Subtract the "weeks early" from the chronological age to get the Adjusted Age.
What Your Adjusted Age Means
The adjusted age number indicates which developmental milestones your baby should be reaching right now. It effectively resets the clock to the due date, giving a realistic view of progress. This number is crucial for evaluating whether your preterm baby is growing as expected.
| Gestational Category | Weeks Early | Recommendation |
|---|---|---|
| Late Preterm (34–36 weeks) | 4–6 weeks early | Use adjusted age for growth charts for the first 12 months. |
| Moderate to Very Preterm (28–33 weeks) | 7–12 weeks early | Use adjusted age for development assessments until age 2. |
| Extremely Preterm (Less than 28 weeks) | 12+ weeks early | Use adjusted age for school entry decisions until age 3 or 4. |
Babies born at 37 weeks or later are full-term and typically do not need age adjustment.
Important Note
Most doctors recommend using adjusted age until your child catches up or reaches age 2. If the gap between chronological and adjusted age causes concern, consult your pediatrician.
Use this corrected age when reviewing growth charts and milestone checklists. *This calculator is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.*
Track your child's progress over time to see if they are closing the gap with their peers.