Calculators
Date difference calculator
Count calendar days between two dates, with an optional inclusive count.
Calculation
Calculated in your browser. Your entries are not uploaded.
Calculated in your browser. Your entries are not uploaded.
How to use this calculator
- Choose the calculation and input format.
- Enter your values or load the worked example.
- Read the result, then copy or download it as text.
Calculation rules
Dates use the Gregorian calendar from year 0001 through 9999. Elapsed days exclude the start date: 2024-01-31 to 2024-02-29 is 29 days. Including both dates gives 30 counted days. Time of day, local daylight saving changes and time zones do not change the result.
Questions and answers
How are whole months and inclusive days counted?
The calendar breakdown advances whole months from the original start date and clamps to the last valid day of the target month. January 31 to February 29 is therefore one month. The years/months/days breakdown always describes elapsed time, even when inclusive day counting is selected.