Should I include the end date?
By default, the count is the number of days you move forward from the start to reach the end, so Monday to Tuesday is 1 day. Tick “include the end date” when both the first and last day count, such as a hotel stay counted in days, a leave request or a 30-day challenge.
How are business days counted?
Business days are Monday to Friday in the same range. Public holidays differ by country and year, so they are not removed; subtract them yourself if needed.
Adding months to the end of a month
Adding one month to 31 January gives 28 February (or 29 in a leap year), because February has no 31st. Years and months are added first, then weeks and days, which is how most calendars and contracts handle it.
Is anything sent to a server?
No. Every calculation runs in your browser. Nothing you type here is uploaded or stored anywhere else.