Explanation
Following order of operations, Excel first calculates the difference between the values (the actual change in sales) then divides that result by the original, or “old” value to get the decimal value -0.3435:
=(D6-C6)/C6
=(49500-75400)/75400
=-25900/75400
=0.0688
Note: you must format the result using Percentage number format to display the final result as 7%
Explanation
In this example, the goal is to determine the percentage discount for each item shown in the table, given an original price and a sale price. In other words, given the Charcoal grill has an original price of $70.00 and a Sale Price of $59.50, we want to calculate a percentage discount of 15%, based on a price decrease of $10.50. Note that a discount of 15% represents the price change ($10.50) expressed as a percentage of the original price. To solve for the percentage when the price change is known, we can use a general formula like this:
original_price*x=price_change
x=price_change/original_price
x=10.50/70.00
x =0.15
However, since the price change is not in the table as a separate column, we need to add a step:
original_price*x=price_change
original_price*x=(original_price-sale_price)
x=(original_price-sale_price)/original_price
x=(70.00-59.50)/70.00
x=10.50/70.00
x =0.15
Applying this approach to the worksheet as shown, the formula in cell E5, copied down, is:
=(C5-D5)/C5
=(70-59.5)/70
=10.5/70
=0.15
For each item in the table, Excel returns a calculated percentage.
Formatting percentages in Excel
In mathematics, a percentage is a number expressed as a fraction of 100. For example, 75% is read as “Seventy-five percent” and is equivalent to 75/100 or 0.75. Accordingly, the values in column E are decimals. To display these numbers as a percentage with the percent sign (%), the Percentage number format has been applied to E5:E15.
