How to calculate percentage decrease in Excel

You can watch a video tutorial here.

Excel is frequently used for calculations and supports all basic mathematical operations.  You may need to find by what percentage a number has decreased when comparing two sets of numbers. Assume you know that the sales in your branch outlets have declined. You would like to understand the magnitude of the decline by measuring the percentage decrease. The formula for this calculation is:

((New number – Old number)/Old number)*100

Step 1 – Divide the difference in numbers by the first number

– In the destination cell type the formula using cell references:
=(Sales Feb – Sales Jan)/ Sales Jan

Step 2 – Format the number as a percentage

– Select the cell with the value
– Go to Home > Number
– Click on the percentage sign (%)
OR
Open the Format Cells window (Home > Number and click on the arrow to expand the menu OR Right-click and select Format Cells  from the context menu OR Go to Home > Cells > Format > Format Cells) and select Number > Percentage and click OK

Step 3 – Copy the formula

– Using the fill handle from the first cell, drag the formula to the remaining cells
OR
a) Select the cell with the formula and press Ctrl+C or choose Copy from the context menu (right-click)
b) Select the rest of the cells in the column and press Ctrl+V or choose Paste from the context menu (right-click)