Question: how to calculate percentage decrease in excel?
Answer: First, click in cell B3 to apply the Percentage format to the cell. On the Home tab, click the Percentage button. ... 
In cell B3, divide the second year's sales ($598,634.00) by the first year ($485,000.00), and then subtract 1.
Here's the formula in cell C3. =(B2/A2)-1.