About ChronoAge Pro

ChronoAge Pro is a free, focused tool for the professionals who compute chronological age every working day: speech-language pathologists, school psychologists and educational diagnosticians. It returns the exact age inyears; months; days between a child's date of birth and thetest date — the way standardized assessments require it for valid scoring.

What makes it different

The math is the product, and it is checked. The age calculation is unit-tested against worked examples, counts leap years, and handles month-end dates correctly, so the number always matches a careful date-difference. Every result has a“how we calculate this” view — no black boxes.

Built for a caseload, not one child. The Caseload mode scores a whole roster in one pass. A rounding toggle covers the exact, years-and-months, and round-at-15 conventions, and a corrected-age mode handles prematurity. These are the parts every generic age calculator leaves out.

No accounts, no friction, private by design. There is nothing to sign up for. Everything runs in your browser, works offline after the first visit, and children's dates of birth never leave your device — caseload rows live only in your browser's local storage.

Where the numbers come from

The core calculation is the standard calendar elapsed-time method (equivalent to a careful date library such as dateutil.relativedelta). Per-assessment rounding conventions are sourced from each test's own manual or scoring guidance and cited on that test's page; where a convention cannot be sourced, we say so and show the exact age plus the toggle rather than inventing a rule. Assessment names are trademarks of their publishers, used descriptively only — ChronoAge Pro is not affiliated with or endorsed by any publisher.

If a number ever looks wrong or a tool could be clearer, we would genuinely like to hear about it — see the contact page.