Enter a start date (like a birthday) and an end date to get the exact difference in years, months, and days.
Runs entirely in your browser — nothing you type here is sent to our server.
A quick way to estimate someone's age is to divide the number of days they've been alive by 365.25. It's close, but not exact — months vary between 28 and 31 days, and leap years add an extra day roughly every four years, so a pure division drifts slightly depending on exactly which months and leap years fall inside the range being measured. Over a long span, like a full lifetime, that drift can add up to a day or more of apparent error.
This calculator instead counts the way a calendar actually works: it finds the full years between the two dates, then the full months left over, then the days left over after that — the same process you'd follow counting by hand on a physical calendar. The result is exact, matching what you'd get counting manually, with no rounding or approximation involved.
Written from what each site tells us about itself and how the directory works — see something off? Let us know.
The calculator finds the calendar-accurate difference between the two dates — the same way you'd count on a calendar by hand — rather than simply dividing the total number of days by 365. That matters because calendar years and months don't all have the same length, so a simple division can be off by a day or more, especially across leap years.
It counts the largest number of whole calendar months it can add to the start date without passing the end date, clamping to the last real day of a shorter month when needed — so January 31 to February 28 counts as exactly one month, and the extra day to March 1 shows up as 1 month, 1 day. The same clamping handles a February 29 start date landing in a non-leap year.
Yes. Enter today's date as the first date and the future date as the second; the breakdown works the same way regardless of which date comes first.
No. The calculator works with calendar dates only, not specific times of day, so it gives the same result no matter what time zone you're in.
Total hours (and total days and weeks) are calculated from the exact number of calendar days between the two dates, so they're exact, not estimates — unlike the reading-time-style estimates you'll find on some of our other tools.
