Discount calculator
Find the sale price, the savings, or the original price.
Enter the original price and the discount percent.
- Stack two discounts
- Work backward from a sale price
- Updates as you type
How to calculate a discount
- Pick single, stacked, or reverse.
- Type the price and discount percent.
- Read the amount saved and the resulting price.
The math behind each mode
- Single discount: sale price = price x (1 - discount / 100). 30% off $45 is 45 x 0.7 = $31.50.
- Stacked discounts: sale price = price x (1 - first / 100) x (1 - second / 100). 15% then 10% off $200 is 200 x 0.85 x 0.9 = $153.
- Reverse: original price = sale price / (1 - discount / 100). A $60 sale price at 25% off came from 60 / 0.75 = $80.
Stacked discounts vs adding the percentages
A second discount always works on a price that is already lower, so a stack saves less than the two percentages added together. In stacked mode, the calculator shows the single discount the stack equals.
| Discounts | Added together | Real discount | Price of a $100 item |
|---|---|---|---|
| 20% then 10% | 30% | 28% | $72.00 |
| 15% then 10% | 25% | 23.5% | $76.50 |
| 25% then 25% | 50% | 43.75% | $56.25 |
| 30% then 20% | 50% | 44% | $56.00 |
| 50% then 20% | 70% | 60% | $40.00 |
The gap grows with the size of the discounts. A "50% off, plus an extra 20% off" sale takes 60% off in total, not 70%.
Working back to the original price
A sale price is the original price times what is left after the discount. Divide by that remainder to undo it. If you paid $42 at 30% off, the original was 42 / 0.7 = $60, so you saved $18. A $90 item marked 40% off was originally 90 / 0.6 = $150.
Adding the percentage back on does not work. $42 plus 30% is $54.60, not $60, because the 30% was taken from the larger original price. Reverse mode also expects the price you paid, not the amount you saved.
Discount calculator FAQ
What is 25% off $80?
25% off $80 saves $20, for a sale price of $60.
How do stacked discounts work?
Each discount applies to the price left after the one before it. A $100 item with 20% off, then an extra 10% off, ends at $72, not $70, an effective 28% off.
How do I find the original price from a sale price?
Use reverse mode. A $60 sale price after 25% off means the original price was $80, since 60 divided by 0.75 is 80.
Why isn't a 20% and 10% stack the same as 30% off?
The second discount applies to an already-reduced price, so the combined saving is always a little less than adding the two percentages.
What is 30% off $45?
30% off $45 saves $13.50, for a sale price of $31.50.
What is a $200 item with 15% off, then an extra 10% off?
The price ends at $153, an effective 23.5% off, not 25%. Each discount applies to what is left after the one before it.
Does the order of stacked discounts matter?
No. 20% then 10% and 10% then 20% both leave 72% of the price, because the two multipliers, 0.8 and 0.9, give the same product in either order.
Can I apply more than two discounts in a row?
This tool stacks two at a time. For a third discount, take the sale price this tool gives you and run it back through single mode with the third percentage.