Single discount vs stacked discounts
A standard discount is straightforward: multiply the original price by the percentage off, then subtract the savings. Stacked discounts are where shoppers and merchants often misread the math. If a product is 20% off and you add another 10% coupon, the total discount is not 30% off the original price. The coupon applies to the reduced subtotal.
On a $100 item, 20% off lowers the price to $80. A second 10% discount removes $8 more, leaving a final price of $72. The total savings are $28, which means the effective discount is 28%.
Why this matters for real buying decisions
This is one of the simplest high-frequency utility calculators on the web because the use case is constant. People use it for online shopping, retail markdowns, coupon stacking, comparison shopping, and resale pricing. The difference between estimated and actual checkout cost gets even larger once sales tax or VAT is added, so discount math works best alongside a tax calculator.
How to use the result
- Compare two promotions with the same starting price.
- Estimate real savings before tax and shipping.
- Check whether a second coupon meaningfully changes the price.
- Convert markdowns into an effective percentage off for reporting.