You can use Excel to quickly calculate the percentage of change between two values. In our simple example, we show you what you need to know to be able to calculate things like how much the price of gas changed overnight or the percentage rise or fall in a stock price.
How the percentage of change works
The percentage of change between an original value and a new value is defined as the difference between the original value and the new value, divided by the original value.
(new_value - original_value) / (original_value)
For example, if the price of a gallon of gas was $2,999 yesterday on your ride home and went up to $3,199 this morning when you filled your tank, you could calculate the percentage of change by plugging those values into the formula.
($ 3.199 - $ 2.999) / ($ 2.999) = 0.067 = 6.7%
Let’s look at an example
For our simple example, we will look at a list of hypothetical prices and determine the percentage change between an original price and a new price.
This is our sample data containing three columns: “Original Price”, “New Price”, and “Percent Change”. We have formatted the first two columns as dollar amounts.
Start by selecting the first cell in the “Percent Change” column.
Type the following formula, and then press Enter:
= (F3-E3) / E3
The result will appear in the cell. It is not yet formatted as a percentage. To do that, first select the cell that contains the value.
In the “Start” menu, navigate to the “Numbers” menu. We’ll use two buttons: one to format the cell value as a percentage, and one to reduce the number of decimal places so that the cell only displays the tenths place. First, press the “%” button. Then press the button «.00 ->. 0”. You can use any of the buttons on the right side of the menu to increase or decrease the displayed precision of the value.
The value is now formatted as a percentage and only a decimal is displayed.
Now we can calculate the percentage of change for the remaining values.
Select all the cells in the “Percent Change” column, and then press Ctrl + D. The Ctrl + D shortcut fills the data down or to the right in all the selected cells.
Now that we are done, all the percentages of change between the original prices and the new prices have been calculated. Note that when the “New Price” value is less than the “Original Price” value, the result is negative.