Calculate the exact interval between two dates in several units.
Converting both dates to a day count makes the difference a simple subtraction and handles leap years and varying month lengths correctly. Months and years are derived from average lengths. Counting days by hand across month boundaries is where date arithmetic usually goes wrong, especially across a February in a leap year.
Time Between Dates
Days between = day number of the end date − day number of the start date
Days between = day number of the end date − day number of the start date Converting both dates to a day count makes the difference a simple subtraction and handles leap years and varying month lengths correctly. Months and years are derived from average lengths.
Counting days by hand across month boundaries is where date arithmetic usually goes wrong, especially across a February in a leap year.
This calculator takes 6 inputs: Start date year, Start date month, Start date day, End date year, End date month, End date day. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.