Coupon Stack Calculator

Work out what a purchase actually costs once several coupons land on the same order. The calculator applies each discount in turn, so a percentage coupon acts on a price that an earlier coupon has already reduced, then charges sales tax and credits any cashback on the same reduced figure.

How a Stack of Coupons Resolves Into One Price

The calculator treats a pile of coupons as a sequence of subtractions rather than a set of independent allowances. Each code runs against the balance that the previous one left behind, which is why the position of a coupon in the chain changes what it is worth. Every entry carries a description, a type and a value, and the page keeps a running total as it walks down the list.

• Coupons are applied one after another. A 20 percent code used second is worth 20 percent of whatever the first coupon left, not 20 percent of the shelf price.
• Percentage coupons scale with the running balance, so their dollar value shrinks each time a discount ahead of them has already cut the price.
• Dollar-off coupons are clamped to the balance still on the table. Their contribution is the smaller of the coupon's face value and the current price, so a large fixed coupon cannot push the total below zero.
• Four application orders are offered: as listed, percent coupons first, fixed coupons first, and a best-for-customer mode that evaluates both stacked orders and keeps whichever one leaves the lower final price.
• Sales tax is calculated on the post-coupon balance, and cashback is credited on the same figure, so both move with how well the stacking worked.
• The headline savings number adds the coupon discounts to the cashback and measures the sum against the original price, which is why a 20 percent coupon paired with 5 percent cashback reads as roughly a quarter off rather than 25 percent.
• Out of the box the page holds a $100 item, 8 percent tax, no cashback and an empty coupon list, and returns a final price of $108.00 with 0.0 percent saved.

Building a Stack Step by Step

1. Type the original price, the tax rate and the cashback rate. Leaving cashback at zero is fine if the purchase returns no rewards.
2. Press Add Coupon once for each code you hold. Each row takes a label, a type (percent off or dollar off) and a value.
3. Only coupons with a value greater than zero are counted; an empty or zero row is ignored rather than treated as a free discount.
4. Pick an application order in the dropdown. As listed keeps the rows in the order you typed them, the percent-first and fixed-first options re-sort the list, and best for customer tries both orderings and keeps the cheaper one.
5. Press Calculate to produce a table that shows each coupon's dollar contribution, the running total, the tax line, the cashback line and the final price.
6. Read the savings banner at the bottom. It is the figure to quote when comparing two orderings, because it folds cashback in alongside the coupon discounts.
7. Copy any numbers you need before closing the tab; the page keeps no record between visits.

Two Coupons, Several Orderings, Several Prices

Take a $100 item with 8 percent tax and 5 percent cashback, and one $20-off coupon plus one 20 percent coupon. The same two codes produce different totals depending on which one the calculator is told to run first.

• Fixed coupon first, then the percentage: $20 comes off 100 to leave 80, then 20 percent of 80 is 16. The coupon column totals $36.00, the discounted price is 64.00, tax is 5.12 and cashback is 3.20, so the final price is 65.92 and savings read 39.2 percent.
• Percentage first, then the fixed coupon: 20 percent of 100 is 20, leaving 80, and then $20 comes off to leave 60. The coupon column totals $40.00, the discounted price is 60.00, tax is 4.80 and cashback is 3.00, so the final price is 61.80 and savings read 43.0 percent.
• The best-for-customer setting applied to that same pair evaluates both stacked orders and keeps the cheaper one, so it returns the percent-first total of 61.80 rather than the higher 65.92.
• The four-dollar gap is entirely positional: when the percentage is taken first it is calculated on the full 100, and more discount survives into the final price.
• With the coupon list cleared, the same $100 purchase returns a final price of 108.00 and a savings figure of 0.0 percent, which is the baseline the other totals are measured against.

Approaches to Sequencing a Stack

Alternative	Notes
Mirror the register	Enter the coupons in the order a cashier would scan them and leave the setting on as listed. This is the honest model when the store dictates the sequence, and it is the only ordering that can be checked against a real receipt.
Percentage before fixed	Put every percent code ahead of the dollar-off codes. With the default figures this produces the largest coupon total, because the percentage is charged against the higher, pre-discount balance, and a bigger discount then carries through to the end.
Fixed before percentage	Do the dollar-off deductions first. It feels orderly because the price comes down in whole dollars, but the percentage that follows is charged on a smaller number, so the coupon total is smaller than the percent-first route whenever the two are mixed.
Manual side-by-side	For two or three coupons, run the calculation once under each ordering and compare the final price directly. The difference is largest when a big percentage and a big fixed coupon meet, and smallest when one type dominates the stack.

What the Page Does Not Know About Your Coupons

The arithmetic runs entirely in the browser and nothing you type is transmitted. That convenience comes with a limit worth understanding: the calculator models coupon values, not coupon rules, so it will happily stack combinations a real checkout would reject.

• Minimum-spend conditions are not checked. A coupon that requires a $50 basket is applied to whatever price you entered, even if that price is below the threshold.
• Mutual-exclusion terms are ignored. Real promotions often forbid combining two offers, but the page stacks everything you enter.
• Category and brand restrictions do not exist here; a coupon is a number with a label, so it applies to the whole basket.
• Only two coupon types are modelled, percent off and dollar off. Free-shipping promotions have no representation, since they change the delivery charge rather than the item price.
• Expiry dates, single-use limits and per-account restrictions are not part of the model and would need to be tracked separately.
• Nothing is stored. The rows, the order setting and the results disappear when the tab is closed or reloaded.

Coupon Stacking Questions

Why is my second coupon worth less than its printed value?

Because a percentage coupon is charged against the price after the coupons ahead of it have already been applied. A 20 percent code sitting behind a coupon that removed $20 is calculated on $80, so it contributes $16. A dollar-off coupon never grows or shrinks, but it can be clamped if the remaining balance is smaller than its face value.

Does the application order really change the total?

Yes, whenever the stack contains both a percentage coupon and a dollar-off coupon. With a $100 item, a $20 coupon and a 20 percent coupon, running the fixed coupon first gives a discounted price of $64 while running the percentage first gives $60. The lower figure follows from charging the percentage against the larger, untouched balance.

What does the best-for-customer setting actually choose?

It runs the same stack both ways, percent coupons first and fixed coupons first, and keeps whichever produces the lower final price. Its result can therefore never be dearer than either single ordering. In a mixed stack of one $20 coupon and one 20 percent coupon it returns the percent-first total of 61.80 rather than the fixed-first 65.92, because charging the percentage against the larger, untouched balance removes more.

Is sales tax applied before or after the coupons?

After. The tax rate is charged on the discounted balance, not on the original price, and cashback is credited on that same discounted balance. Changing the coupons therefore changes the tax line and the cashback line together.

Does cashback count towards the savings percentage?

Yes. The savings banner adds the coupon discounts to the cashback amount and divides by the original price, so a purchase with coupons plus a cashback rate shows a higher percentage than the coupons alone would suggest. The cashback figure is also credited in the final price before the savings banner is calculated.

Last verified: October 3, 2026

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Maintained by Huang Bin · Last updated October 3, 2026