Running Average

emmaballer 

Since you're in (I trust) the early stages of creating this budget spreadsheet, I'm going to suggest you change your approach and let Excel do the "heavy lifting" of giving you your monthly averages, your monthly totals, etc., by category.

To do that, have just a single sheet into which you enter the date for each check or credit card purchase (or download those from your banks), an indication of the expense category, etc.  Then use the Pivot Table capability of Excel to do that "heavy lifting" that you want it to do.

I'm attaching a very simple example just to show you how that can work. There are two Pivot Tables in this workbook.

• The one labeled "Annual Summary" displays the sum total of expenses in each category for the year selected, as well as the averages for that year.
• The one labeled "Monthly Summary" displays the totals for each category for each month in the years 2019 and 2020. That could be modified so it only does one year. In fact, it can be modified in all sorts of ways.

Let me encourage you to play around with this way of doing it. Add some expenses. Add some expense codes in the "Codes" tab... Then when you're in the Pivot Table tabs, just click on the "Refresh" button (in the image below, it's under the word "Design") to see how the Pivot Table automatically adds in those new pieces of information.