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Age Calculator
Find exact years, months, and days from a date of birth. Optionally calculate as of a custom date.
Date inputs stay in your browser · nothing is uploaded
Dates
Local calendar math
Results
Updates live
/age-calculator
How it works
Four steps that match this page. Everything runs in your browser.
- 1
Enter date of birth
Pick a date of birth. The calculator uses your local calendar.
- 2
Optionally set as-of date
Stay on As of today, or choose As of custom date and pick the date you want.
- 3
Read Y/M/D cards
Years, months, and days show in the sticky Results panel as you edit.
- 4
Check totals and next birthday
Total Days, Total Weeks, and the next birthday countdown sit under the age cards.
Frequently Asked Questions
Job answers for exact age, leap days, as-of dates, next birthday, and privacy.
How is exact age in years, months, and days counted?
Full calendar years come first. Then full months. Then the leftover days. If the day of the month has not arrived, the month count steps back and the days come from the previous month.
How are leap days counted?
February 29 counts as a calendar day. Years, months, and days follow the calendar, not a 365.25 day average. In a non-leap year a February 29 birthday uses March 1 for the next birthday countdown.
What does the as-of date do?
As of today uses the local calendar date on this device. As of custom date calculates age on the date you pick. The date of birth has to be earlier than that date.
How does the next birthday countdown work?
Next Birthday counts the days from the as-of date to the next date of birth. The date under the count is that upcoming birthday.
Do my date of birth inputs leave this device?
No. Date of birth and the as-of date stay in your browser. Nothing is uploaded. There is no account.