When you know the sale price and discount, divide by the percentage that was paid. This is a reverse percentage calculation, not a matter of adding the discount back.
Find the percentage paid
Subtract the discount from 100%. If an item is 25% off, the customer pays 75% of the original price, or 0.75 as a decimal.
Divide the final price
If the sale price is $60 after 25% off, calculate $60 ÷ 0.75. The original price was $80.
Why adding 25% is wrong
Adding 25% of $60 gives $75, not $80, because the 25% discount was based on the larger original price. Reverse percentages must use division.
Account for several discounts
If multiple percentage discounts were applied, multiply their remaining factors first. A 20% and then 10% discount leaves 72%; divide the final price by 0.72.
A calculator is often the quickest way to check your mental math. The important part is using the right starting value.
Open a calculator →Common questions
A $72 item is 20% off. What was the original price?
$72 ÷ 0.80 = $90.
Can I add the discount percentage back?
No. The sale price and original price use different bases.
What if the discount is 100%?
The original price cannot be recovered from a final price of zero without additional information.
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