Age calculator
How many days have you been here?
Enter a date of birth for an exact age down to the day, the running total in days, weeks and hours, the weekday it all started on, and the next round-number day worth a small celebration.
Dates stay in this page. Nothing is saved or sent, and the share button sends only the totals.
Free tool from Pocket Puzzle Arcade
How your age is counted
Age in years, months and days is counted the way a calendar does it: whole years since your last birthday, whole months since then, and the days left over. The total in days is simpler: the number of midnights between your birth date and the date chosen, leap days included.
The thousand-day milestones
Birthdays come round once a year. Round numbers of days come at odd times, and nobody expects them. Your 10,000th day arrives when you are 27 years and about four and a half months old. The 15,000th falls a little after your 41st birthday, the 20,000th at 54 and three quarters, and the 25,000th at 68 and a bit. The calculator tells you which one is next and the date it lands on.
| Milestone | Age when it happens |
|---|---|
| 5,000 days | About 13 years, 8 months |
| 10,000 days | About 27 years, 4½ months |
| 15,000 days | About 41 years, 1 month |
| 20,000 days | About 54 years, 9 months |
| 25,000 days | About 68 years, 5 months |
| 30,000 days | About 82 years, 2 months |
Leap days
A year is a leap year if it divides by four, except century years, which must divide by 400. So 2000 was a leap year and 1900 was not. Anyone born on 29 February has a birthday that exists one year in four; most celebrate on 28 February or 1 March in between.
The weekday you were born
The calculator works it out from the calendar. An old rhyme assigns a character to each day, from "Monday's child is fair of face" onward. It is a rhyme, not a forecast.
Questions people ask
How do I work out how many days old I am?
Count the days from your date of birth to today, including leap days. Someone born on 21 March 1995 is 11,557 days old on 10 November 2026.
How old will I be when I am 10,000 days old?
About 27 years and four and a half months. The exact date depends on how many leap days fall in between.
How is age in years, months and days calculated?
Count whole years since the last birthday, then whole months since that date, then the remaining days.
Like puzzles from the past? Take a case.
PastRush: History Detective is an iPhone and iPad game where you weigh evidence and decide what really happened. Its listing includes six free investigations, among them the Rosetta Stone, Pompeii and Ötzi, plus a daily evidence check.
Get PastRush on the App StoreSix investigations are free; an optional one-time Founder Lifetime purchase unlocks cases 7 to 12. The listing says no subscription. Check the App Store for current details.
Honest Little Apps publishes both PastRush and this page. This is a separate browser tool and does not sync with the app. App details checked November 10, 2026.
On a computer? Open it on your iPhone
