Find the exact difference between two dates, or add/subtract a duration from a date —
calendar-accurate down to the second.
How to use this calculator
Choose Difference or Add/Subtract, then fill in the fields — the result appears
underneath as soon as both dates (or a start date) are set. Use the "Now" button to
fill in the current moment.
DifferenceShows the calendar-accurate gap between two dates as years, months, days, hours,
minutes and seconds — e.g. the gap between Jan 31 and Mar 1 is "1 month, 1 day", not a
flat day count — plus flat totals (total days, hours, minutes, seconds) for when you
just need one number.
Add / SubtractAdds or subtracts a duration from a start date. Adding months/years clamps the
day to the target month when it doesn't exist there — e.g. Jan 31 + 1 month lands on
Feb 28 (or 29 in a leap year).
Time zonesAll dates/times are your device's local time — there's no time zone conversion
here (that's a separate tool).