Developmental & early childhood · Pearson
Mullen Age Calculator
Chronological age in years;months.days for the Mullen Scales of Early Learning, with the published age range Birth – 68 months checked for you.
Mullen at a glance
| Full name | Mullen Scales of Early Learning |
|---|---|
| Publisher | Pearson |
| Published age range | Birth – 68 months |
| Age format | Years;months.days |
| Corrected age | Corrected age is commonly used for preterm children until the second birthday, particularly in research protocols where the convention is stated in advance. |
| Discipline | Developmental & early childhood |
The Mullen Scales cover gross motor, visual reception, fine motor and receptive and expressive language from birth. It is widely used in autism research cohorts as well as in clinical early-childhood evaluation.
How the Mullen wants the age entered
Enter the exact chronological age in years;months.days. Early-learning norms are banded in short intervals through the first two years.
The underlying calculation is the same for every instrument — complete years, complete months, then the leftover days. What differs is which part of it goes on the form. The calculator above reports all four figures at once, so you can copy the one the Mullen manual asks for without recalculating:
- Years;months.days — the full record-form format, e.g. 1;6.20
- Years;months — complete units only, e.g. 1;6
- Complete months — e.g. 18 months
- Rounded to nearest month — e.g. 19 months (1;7), using the 15-day threshold
The exact date arithmetic, including month-end clamping and leap-day handling, is documented in the calculation methodology.
Worked example
A child born February 26, 2025 and assessed on September 15, 2026:
- Chronological age: 1 year, 6 months, 20 days
- Record on the Mullen as: 1;6.20
- Day remainder: 20 days — 15 or more, so a nearest-month rounding rounds up
Enter these exact dates above to reproduce the result. Every figure on this page is computed by the same library that runs the calculator, so the worked example and the tool can never disagree.
Corrected age and the Mullen
Corrected age is commonly used for preterm children until the second birthday, particularly in research protocols where the convention is stated in advance.
Corrected (adjusted) age is measured from the due date rather than the birth date. Switch the calculator above to Born preterm and enter the gestational age at birth to see both figures side by side. The dedicated adjusted age calculator adds gestational and postmenstrual age, and the corrected age guide explains the convention for families.
Other instruments
Same calculation, different recording format. These are the instruments most often administered alongside the Mullen:
| Instrument | Age range | Age format |
|---|---|---|
| Bayley-4 | 16 days – 42 months | Years;months.days |
| DAYC-2 | Birth – 5:11 | Total months |
| BDI-3 | Birth – 7:11 | Total months |
| ASQ-3 | 1 – 66 months | Total months |
| ASQ:SE-2 | 1 – 72 months | Total months |
| Denver II | Birth – 6:0 | Years;months.days |
The full list is on the assessment instrument reference, and the assessment age calculator covers any instrument not listed individually.
Mullen, Pearson are trademarks of their respective owners. AgeCalc is not affiliated with, endorsed by, or sponsored by any of them. Brand names are used descriptively to identify the assessment formats this calculator supports.