=IF(A1>B1,B1-A1,A1-B1)
=(B1-A1)/B1
Re-reading your original post, asking for increase or decrease, do you mean it'll always be the change from the value in 1st column to the value in the second column? If so, then can't you just use:
Then format as percentage and drag down all your rows?Code:=(B1-A1)/B1