"20% off, plus an extra 10% off" is not 30% off. Enter multiple discounts and see the real final price.
Enter the shelf price, then add each discount as its own percentage in the order the store applies them. A single "25% off" is one row. "20% off, then an extra 10% off at the register" is two rows. The optional tax rate is applied after every discount, which is how most US jurisdictions treat a store discount. The result shows the final price, the money saved, and the real percentage off.
Number the rows in the order the discounts happen, because the order changes nothing about the total but does change how you check it against the receipt.
A $100 jacket with a 20% sale tag and a 10% email-code discount:
| Step | Price |
|---|---|
| Starting price | $100.00 |
| After 20% off | $80.00 |
| After a further 10% off $80 | $72.00 |
| With 6% sales tax | $76.32 |
The real discount is 28%, not 30%, because the second percentage came off a smaller number. The missing 2% is $2, and on a $600 purchase it is $12 — the reason a "30% off everything" coupon that is really two stacked 15% codes is worth less than it reads.
Reverse the order and the total is identical: 10% takes $100 to $90, and 20% of $90 is $18, leaving $72. Stacked percentages multiply, and multiplication does not care about order. Only the labels on the receipt do.
Three numbers matter and they answer different questions. The final price is what leaves your account. The amount saved is what the sale is worth to you in cash. The effective percentage is the honest headline, and it is the number to compare between two stores that advertise differently.
Tax placement is the detail that makes results disagree with a receipt. Some states tax the pre-discount price when the discount is a manufacturer's coupon, because the store is reimbursed by the manufacturer and the full price was the sale. Store discounts are usually taxed on the reduced price. This page takes the common case: tax after all discounts. If a receipt disagrees by a few cents, that is the likely reason.
What the calculator cannot see is whether you would have bought the item at full price. A 40% discount on something you did not need is a 100% loss. That is not arithmetic, but it is the number that actually matters.
Because the second discount is charged on what is left, not on the original price. Percentages of a shrinking number do not add; they multiply.
Not for the total. It matters only when one discount has a floor, such as "20% off but not below $60", and the tool has no way to know about that rule.
Enter it as 50% off when you are buying two of something you would have bought anyway. It is not 50% off if the second item is the only reason you are there.
Sometimes, and the store decides. Put both percentages in and compare the total against the register; if they differ, the coupon likely excludes sale items.
That is the same as stacking, because the lowest price is already reduced. Enter each markdown as its own row in the order they were applied.
Successive discounts multiply. Sales-tax rates, if you need one to type, are published by states and summarized nationally.
Last updated: November 2, 2026. Reviewed by David Liu.