1] Add days directly If the expiry period is defined in days, you can calculate the expiry date by simply adding the number of days to the starting date using the + operator.

How to Calculate Hours in Excel Excluding Weekends. An Excel spreadsheet can become an indispensable tool for your business when you harness its power for keeping records and doing computations.

You should have experience with Excel before trying to use formulas to calculate what day of the week the 15th of a given month is, and you have several options to do this.