Year Calculator
Calculate your exact age in years, months, and days given your birth date. Also add or subtract years from any date to find past or future dates.
About this Calculator
Calculate your exact age in years, months, and days given your birth date. Also add or subtract years from any date to find past or future dates.
Formula & Calculations
Formula
Age = Current Date − Birth Date (broken into years, months, and days); Result Date = Start Date ± N yearsWhere:
- Birth Date=The person's date of birth
- Current Date=Today's date (or a custom reference date)
- Years=Number of full years elapsed
- Months=Remaining full months after subtracting years
- Days=Remaining days after subtracting years and months
Assumptions
- Age calculation respects the exact calendar date (you are not one year older until your birthday passes).
- Leap years are properly accounted for in day counts.
- Adding/subtracting years maintains the same month and day, adjusting for Feb 29 if needed.
Calculation Examples
Example 1
36 full years have passed. The last birthday was June 15, 2026 (9 days ago).
Example 2
2028 is a leap year, so Feb 29 exists. Adding 4 years to Feb 29, 2024 yields Feb 29, 2028.
Example 3
2025 is not a leap year, so the date is clamped to Feb 28.
Frequently Asked Questions
How is age calculated precisely?
The calculator subtracts the birth year from the current year, then checks if the birthday has occurred yet this year. If not, it subtracts one year. Months and days are then computed from the last birthday.
What happens with February 29 births in non-leap years?
The age calculation still works correctly. In non-leap years, the 'birthday' is treated as March 1 for month/day breakdown purposes, since Feb 29 doesn't exist.
Can I use this to project future dates?
Yes. The add/subtract years mode lets you enter any start date and any number of years (positive or negative) to find the resulting date.