Adjusted Age Calculator
Calculate your baby's developmental age based on prematurity.
What is Adjusted Age?
Adjusted age (or corrected age) is the age a premature baby would be if they had been born on their actual due date. Doctors use this measurement to track a preemie's growth and developmental milestones more accurately during the first two years of life.
A "full-term" pregnancy is considered 40 weeks. If a baby is born at 32 weeks, they are 8 weeks premature. This "missing time" in the womb affects when they might sit up, crawl, or reach other physical markers compared to babies born at full term.
The Formula for Calculation
The calculation follows a simple two-step logic:
- Step 1: Calculate the Weeks Premature (40 weeks – Gestational Age at Birth).
- Step 2: Subtract the Weeks Premature from the baby's actual Chronological Age.
A baby born at 30 weeks gestational age is now 20 weeks old (chronological age).
1. Weeks Premature: 40 – 30 = 10 weeks.
2. Adjusted Age: 20 – 10 = 10 weeks.
The baby is 20 weeks old, but should be meeting milestones typical of a 10-week-old.
Developmental Milestones and Adjusted Age
| Milestone | Chronological Age (Preemie) | Adjusted Age (Target) |
|---|---|---|
| Social Smile | 8-12 Weeks | ~2 Months |
| Rolling Over | 6-8 Months | ~4-6 Months |
| Sitting Alone | 8-10 Months | ~6-8 Months |
When to Stop Using Adjusted Age?
Most pediatricians and developmental specialists recommend using adjusted age until the child reaches 2 years of age. By this point, most premature children have "caught up" to their peers in terms of height, weight, and cognitive development. If a child was extremely premature (born before 28 weeks), some specialists may monitor adjusted age for a bit longer.
Why is this Important for Parents?
Using the adjusted age helps reduce parental anxiety. If a 6-month-old preemie isn't sitting up yet, it might be because their adjusted age is only 3 months. Knowing the adjusted age provides a realistic window for development and ensures that early intervention is suggested only when truly necessary based on the corrected timeline.