Finding the original price before discount is useful when you know the sale price and the percentage off, but not the starting price. This is the reverse of a normal discount calculation. Instead of subtracting a discount from the original price, you work backwards from the discounted price.
Use the calculator to check your own numbers, then read the guide for formulas, examples, and common mistakes.
What Original Price Before Discount Means
The original price before discount is the price before any percentage off was applied.
For example, if an item is now 80 after a 20% discount, the original price was not 100 minus 20. Instead, 80 represents 80% of the original price.
This is why the reverse discount formula is slightly different from the normal discount formula.
Original Price Before Discount Formula
The formula is: original price = sale price ÷ (1 - discount percentage ÷ 100).
This works because the sale price represents the remaining percentage after the discount.
If the discount is 20%, the sale price is 80% of the original price.
Example: Sale Price and Discount Percentage
Suppose the sale price is 80 and the discount is 20%.
The remaining percentage is 100% - 20%, which equals 80%.
Original price = 80 ÷ 0.80 = 100.
Why You Should Not Add the Discount Back Directly
A common mistake is adding the discount percentage to the sale price. For example, adding 20% to 80 gives 96, not 100.
That happens because the discount was taken from the original price, not from the sale price.
To reverse the discount correctly, divide by the remaining percentage.
Another Example
Suppose an item is now 150 after a 25% discount.
A 25% discount means the sale price is 75% of the original price.
Original price = 150 ÷ 0.75 = 200.
How This Connects to Sale Price
Sale price after discount starts with the original price and subtracts the discount.
Finding original price before discount starts with the sale price and works backwards.
For the forward calculation, read How to Calculate Sale Price After Discount.
Original Price vs Discount Amount
The original price is the starting price. The discount amount is the money removed from that starting price.
Once you know the original price, you can calculate the discount amount by subtracting the sale price.
For that calculation, read Discount Amount Formula.
When This Calculation Is Useful
This calculation is useful when a store shows the current sale price and the percentage off but does not clearly show the original price.
It is also useful for checking whether a claimed discount makes sense.
If a price looks confusing, working backwards can help confirm the original price.
Use the Calculator
Use the Discount Calculator for normal discount calculations when you know the original price.
For reverse discount calculations, use the formula in this guide: sale price divided by the remaining percentage.
For the main discount guide, read Discount Formula.
Conclusion
To find original price before discount, divide the sale price by the remaining percentage after the discount.
This avoids the common mistake of simply adding the discount percentage back to the sale price.
Related guides and tools
FAQs
How do I find original price before discount?
Divide the sale price by the remaining percentage after the discount.
What is the formula for original price before discount?
Original price = sale price ÷ (1 - discount percentage ÷ 100).
Why can’t I just add the discount percentage back?
Because the discount was based on the original price, not the sale price.