I have a spreadsheet set up as a budget tool. I have a dynamic named range set up where I enter income (positive values) and expenses (negative values). I'm able to do most of what I want with it, but I can't figure out a non-clumsy way of making a pivot table to show the sum of the negative values only (expenses) within a given time frame.

If I set up a pivot table with Rows = Category (like Rent, Utilities, etc) and Value = Sum of Amount, and then try to use a value filter on my rows column, it wants to filter by sum of amount, and shows me only the entries where income plus expenses for that category equals a negative amount.

I can add amount to the filter, then hand select, or use a slider to select every value that is less than 0, but that's really tedious, and I'd have to re-do it every time I entered a new amount that was less than 0.

I could also add another field to my dataset like Expense Yes/No, or "E" for expense, "I" for income, but that feels clunky and redundant to me, since I already know whether it's income or expense by virtue of whether the amount is negative or positive.

Is there any quick and easy way to display in the value column the sum of the negative values only?