Age Calculator
Calculate exact age in years, months, and days between dates.
Key Terms (Click to expand)
Exact age
Calendar-based difference shown in years, months, and days.
Compare date
The date used to measure age from birth date, defaulting to today.
Total days
Full day count elapsed between birth date and compare date.
Leap year handling
Date math follows calendar boundaries, including leap-year dates.
Tool
Methodology
The calculator uses calendar-based date difference from birth date to compare date:
- Exact age is expressed as years, months, and days.
- Total days is computed from full UTC date difference.
- Total months is derived from complete calendar years and months.
- Compare date must be on or after birth date.
Worked Example
A concrete example with realistic numbers will be added for this route.
Assumptions and Limitations
- Calendar-based age uses date boundaries, not average month/day approximations.
- Time-of-day and timezone offsets are not included in this age estimate.
- Compare date must be on or after birth date.
FAQ
Does this handle leap years?
Yes. The calculation uses calendar-aware date math, including leap-day behavior.
Why not just divide total days by 365?
Exact age is calendar-based, so years/months/days are not derived from flat day averages.
Can I calculate age on a future date?
Yes, as long as compare date is on or after birth date.