Successive discounts apply to the price remaining after each reduction. A 20% discount followed by 10% off does not remove 30% of the original price. Run Discount Calculator once for each reduction, using the first discounted price as the original price in the second run.
Follow the price through both reductions
Consider an illustrative item priced at 100. A 20% discount saves 20 and leaves 80. The second 10% discount removes 8 from that remaining 80, leaving 72. The total saving is 28, which is a 28% reduction from the original 100.
| Stage | Reduction | Price remaining |
|---|---|---|
| Starting price | None | 100 |
| First discount | 20% of 100, or 20 | 80 |
| Second discount | 10% of 80, or 8 | 72 |
Start with tax set to zero when you are checking only the promotions. Enter 100 and 20 for the first calculation, note the price after discount, and enter that price with 10 in the next calculation. Keep the intermediate value rather than copying the final price from a run that already includes tax.
The equivalent calculation is 100 multiplied by 0.80 and then by 0.90. Fraction Calculator can express those remaining shares as 4/5 and 9/10 if you want to inspect the exact arithmetic before rounding.
Compare the saving with the starting price
Use Percentage Calculator to compare the original 100 with the final 72. A 28% decrease agrees with the two-stage calculation. Adding the advertised percentages would incorrectly predict a price of 70.
For two pure percentage reductions, swapping their order produces the same unrounded price because multiplication is commutative. A fixed-value coupon, a minimum-spend threshold or rounding at each stage can change that conclusion. Read the promotion terms rather than assuming every offer behaves like the arithmetic example.
Add the other charges separately
The discount tool supports one percentage discount per run, an optional tax percentage and a setting for when tax applies. It does not supply a shipping field, money-off coupon field or currency conversion. Keep those amounts in a separate calculation and verify which price each charge uses.
Use the currency's appropriate display precision. If a seller rounds individual lines before calculating the receipt total, its result can differ slightly from a calculation that rounds only the final amount. Retain the original price, each reduction and the final charge so the comparison remains understandable.
Before relying on the result, confirm that the second offer actually applies to the discounted price. A displayed pair of promotions does not establish that a shop permits combining them.