Anniversary & Birthday Countdown Calculator
Find the days remaining until your next birthday or anniversary.
Assumptions used in this calculation
- Leap day birthdays: A 29 February original date is treated as 28 February in non-leap years when finding the next occurrence.
- Today's date: Uses the current date in your device's local timezone as the reference point.
About this calculator
Anniversaries, birthdays and other yearly milestones are easy to lose track of amid a busy schedule, and manually counting days to the next occurrence means correctly handling the calendar wraparound once the date has already passed this year. This calculator takes an original date, birth date or the date of a first anniversary, and an event type, then finds the nearest future occurrence matching that month and day, reporting exactly how many days remain (also broken down into months and days), which milestone number (the age turning, or the anniversary year) it will mark, and offering a one-click 'Add to calendar' download that sets up a yearly-repeating reminder. It's useful for planning ahead on gifts, reservations or celebrations, or simply for keeping an accurate running countdown without manually recalculating it every time you check. The trickiest part of this calculation by hand is correctly rolling over to next year once the date has already passed for the current year, along with handling the edge case of a 29 February birthday, both of which this calculator resolves automatically.
Worked example
Birthday on 20 July
Result: Days until next birthday
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