Date Calculator
Month and year shifts clamp to the last valid day. Dates are calendar dates, not elapsed hours or business days.
How it works
Day differences use calendar dates in UTC, so daylight-saving changes do not add or remove a day. A negative difference means the end date is before the start date. Including both dates adds one to the absolute difference. When adding months or years, an unavailable day is replaced by the last day of the target month.
Example
From February 28 to March 1, 2024 there are 2 days, or 3 days counting both dates. January 31, 2024 plus 1 month is February 29, 2024.
Frequently asked questions
Does the calculator account for leap years?
Yes. It follows Gregorian calendar leap-year rules, including the century rule: 2000 was a leap year, but 1900 was not.
Does it exclude weekends and public holidays?
No. This calculator counts calendar days. It does not calculate business days or apply regional holiday calendars.