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Days between dates, or add / subtract days.
The Date Calculator works two ways. In Difference mode it tells you exactly how much time separates two calendar dates — as a total number of days and as a tidy years / months / days breakdown. In Add/Subtract mode it starts from a date and shifts it forward or backward by a chosen number of days, weeks, months or years to give you the resulting date.
It is handy for counting down to deadlines, working out contract or notice-period end dates, checking how long ago something happened, or finding a date that is, say, exactly 90 days from today.
The years / months / days breakdown is counted by calendar, so unequal month lengths (28–31 days) and leap years are handled automatically. In Add/Subtract mode the date is shifted by whole units; when adding months or years the day is clamped to the last valid day of the target month (e.g. Jan 31 + 1 month → Feb 28).
It counts the days between the two dates — effectively the number of nights. To count both endpoints inclusively (common for booking nights or event days), add 1 to the total days shown.
The result is clamped to the last day of the target month. Adding one month to January 31 gives February 28 (or 29 in a leap year), which matches how most date calculators and calendar apps behave.
Yes. February 29 and the extra day in leap years are handled automatically in both the day count and the years/months/days breakdown.
This tool counts calendar days, including weekends and holidays. For working-day counts you would need to subtract weekends and any public holidays separately.