Summary

To calculate the percentage discount from an original price and a sale price, you can use a formula that divides the difference by the original price. In the example shown, the formula in E5, copied down, is:

=(C5-D5)/C5

The result is a decimal value which is formatted with the percentage number format.

Generic formula

=(original_price-sale_price)/original_price

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.

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Dave Bruns

Hi - I'm Dave Bruns, and I run Exceljet with my wife, Lisa. Our goal is to help you work faster in Excel. We create short videos, and clear examples of formulas, functions, pivot tables, conditional formatting, and charts.