I assume your current equation is difference divided by last value
try
difference divided by the absolute value of last month

"Laura" wrote:

I'm trying to set up a spreadsheet that calculates a variance percent between
current month and previous month. The percentages work well until I have a a
negative balance for current month and previous month, and current month has
decreased. I know that its a sign issue, but its making my variance positive
and I know thats wrong. Any clues?