Days between two dates, and the date a number of days from another. Countdowns, contract terms, business days.
Turn it on for anniversaries, hospital stays and anything where the starting day is day one: 100 days from January 1 is April 10. Turn it off for contract terms and countdowns, where January 1 to January 2 is one day. If in doubt, ask which convention the other side uses.
Months are 28–31 days long, so "3 months" can be 89 or 92 days. The calculator shows a calendar-based years/months/days figure separately from the exact day count. If a contract says "3 months", the calendar figure is the one that applies.
Only Saturdays and Sundays are excluded. Public holidays differ by country and year, so subtract those yourself if you need exact working days.
January 31 plus one month has no February 31, so it becomes February 28 (29 in a leap year). This matches EDATE in Excel.
No. The arithmetic runs in your browser.
If the end date is today it is D-Day; three days ahead is D-3; three days past is D+3.
Whole days only. Hours and minutes are shown as conversions in the table.