When shopping in brick and mortar stores, it is not uncommon to come across items selling at certain percentages off.

For example, you may come across a T-shirt selling at 20 percent off, or an electric kettle marked 30 percent off. While many people know what percent off means, a good number of shoppers do not know the percent off calculation.

## Percent off / Discount Formula

Formula: (100 - X) / 100 × Y copy

### Excel / Spreedsheets formula

=((100-cell1)/100)*cell2 copy

Steps:
1. Replace cell1 with the cell contains the percentage.
2. And replace cell2 with the cell contains the number.

A percent off of a product is a traditional discount format that enables buyers to acquire products at lower prices than the original one. For example, when they put 20 percent off on a product whose initial price is \$150, customers should pay:

= (100 - 20) / 100 × 150

= 80 / 100 × 150

0.8 × 150 = \$120

This means the buyer saves \$30. If the product has an additional stackable discount, the purchase price can be calculated by further applying the discount on the price after the first percent off calculation. For instance, if the product in the previous example has a 10 percent off additional stackable discount, the purchase price can be calculated as follows;

= (100 - 10) / 100 × 120

= 90 / 100 × 120

0.9 × 120 = \$108

The buyer pays \$108, saving \$42. One of the most common mistakes people make when calculating product price for items with more than one discount is combining the two discounts before calculating. In our example, they would do something like this;

20 + 10 = 30

0.3 X 150 = \$45

150 – 45 = \$105

This gives a slightly higher discount which is inaccurate. Most people who use this incorrect approach tend to be looking for a shortcut to get the final price without working through phases. These people can use the following direct method.

(0.8 x 150) X 0.9 = 108

In this approach, 20 percent (the first discount) is subtracted from 100 percent and multiplied by \$150 to get the price after the first discount directly. The answer is multiplied by 0.9 percent, which is 10 percent (second discount) subtracted from 100 percent to get the price after the second discount.