Back to calculator
Time & DateGenerated accuracy model review: 2026-05-06
Age Calculator accuracy and testing
This page documents how Calwarden builds trust for this calculator: source notes, regression-style default tests, limitations, assumptions, unit handling, rounding, and visible change history.
Formula source
- The calculator compares the month and day of the current date to the birth date. If the current month/day is earlier than the birth month/day, it subtracts one from the year count and calculates the remaining months and days, accounting for month lengths.
Test cases
Default input regression check
Generated from the checked-in default inputs and calculate function.
Inputs
- Date of Birth: 1990-01-01
- Age At Date: 2026-09-24
Expected outputs
- Exact Age: 36 years, 8 months, 23 days
- Total Days Alive: 13,415
- Next Birthday: In 100 days
Known limitations
- This page documents the checked-in calculator logic and does not certify results for every real-world edge case.
- Use the result as a planning estimate unless the calculator page states a stricter purpose.
Assumptions
- The calculator uses standard Gregorian calendar dates and accounts for leap years.
- Age is measured as chronological time between the birth date and the selected target date.
- The 'next birthday' countdown is based on calendar days and does not adjust for time of day.
Unit handling
- Date of Birth accepts calendar dates.
- Age At Date accepts calendar dates.
Rounding rules
- Number displays use up to 2 decimal places in the calculator UI.
Version history
1.0.0 - 2026-05-06
Generated accuracy and testing page from the current age-calculator calculator definition.
Change log
2026-05-06
Published default regression test documentation and metadata fallbacks for Age Calculator.
Calculator transparency
Accuracy pages are generated from checked-in calculator definitions and can be upgraded with curated review metadata over time.