Let’s say that I have a date. This date is something like the 15th and the 30th of each month. Now I want it to update to the appropriate pay period. In a calculation scenario, I use the pay period to calculate other things. I totally know how to get things to update when they are fields based on money or number values. For example, it is as simple as A1 * C10. C10 would hold a number like 11 for the eleventh pay period. I need to understand how to get a date update based on a calculation if A1 held a date to be constrained to the 15th and 30th of every month. How could is that done in Excel?