Autism · WPS
ADOS-2 Age Calculator
Chronological age in years;months for the Autism Diagnostic Observation Schedule, Second Edition, with the published age range 12 months – adult checked for you.
ADOS-2 at a glance
| Full name | Autism Diagnostic Observation Schedule, Second Edition |
|---|---|
| Publisher | WPS |
| Published age range | 12 months – adult |
| Age format | Years;months |
| Corrected age | For a toddler born preterm, the module decision is usually made on corrected age; document the choice, because the Toddler Module ranges are only months wide. |
| Discipline | Autism |
The ADOS-2 is the semi-structured observational assessment at the centre of most autism diagnostic protocols. Module selection depends jointly on chronological age and language level, so the age is a gating decision rather than just a scoring input.
How the ADOS-2 wants the age entered
Record chronological age as years;months. Age combines with expressive language level to select the module, and the Toddler Module has explicit age boundaries.
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 ADOS-2 manual asks for without recalculating:
- Years;months.days — the full record-form format, e.g. 2;6.19
- Years;months — complete units only, e.g. 2;6
- Complete months — e.g. 30 months
- Rounded to nearest month — e.g. 31 months (2;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 27, 2024 and assessed on September 15, 2026:
- Chronological age: 2 years, 6 months, 19 days
- Record on the ADOS-2 as: 2;6
- Day remainder: 19 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 ADOS-2
For a toddler born preterm, the module decision is usually made on corrected age; document the choice, because the Toddler Module ranges are only months wide.
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 ADOS-2:
| Instrument | Age range | Age format |
|---|---|---|
| GARS-3 | 3:0 – 22:0 | Years;months |
| WISC-V | 6:0 – 16:11 | Years;months.days |
| WPPSI-IV | 2:6 – 7:7 | Years;months.days |
| WAIS-5 | 16:0 – 90:11 | Years;months.days |
| SB5 | 2:0 – 85:0 and older | Years;months.days |
| KABC-II NU | 3:0 – 18:11 | Years;months.days |
The full list is on the assessment instrument reference, and the assessment age calculator covers any instrument not listed individually.
ADOS-2, WPS 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.