Discount Stacking Calculator
Several offers on one price, applied in order, with what each one is actually worth.
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The price
Before anything is taken off.
Discounts, in the order they are applied
Tax and shipping
Measured against the discounted subtotal, which is what most thresholds use.
The usual case, and what store coupons normally do.
Enter a list price to see what the stack comes to.
Step by step
| Step | Price before | Takes off | Price after |
|---|---|---|---|
| Shipping | $0.00 | ||
| Tax | $0.00 | ||
| You pay | $0.00 | ||
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How it works
To work out a stacked discount, apply each offer to the price the previous one left behind — 20% off followed by another 10% off is 28% off, not 30%, because the second is taken from the already-reduced price. Enter the offers above and this page runs them in order.
Every figure here comes from running the discounts one after another rather than from adding up rates, because percentages do not add. A 20% sale followed by a 10% member discount leaves 80% of 90% — 72% of the list price, so 28% off rather than 30%. On a $200 item that gap is $4, and it grows with the number of offers stacked: three 20% discounts sound like 60% off and come to 48.8%. The equivalent single percentage is shown next to the result so the difference is visible rather than assumed.
The order the offers run in also changes the total, and only fixed-amount coupons are affected. A percentage taken from a price is the same wherever it sits relative to other percentages, but a $20 coupon applied before a 25% discount loses a quarter of its value, because the discount then applies to a price the coupon has already reduced. The rule that follows is worth remembering at the till: a fixed-amount coupon is always worth more applied after the percentages. This page shows what your order gives, what the best possible order gives, and the difference between them — retailers are not obliged to use the order that suits you, and many specify one in their terms.
Tax and shipping are included because they change which offer is better. Tax is charged on the discounted price by default, which is the usual case for store coupons; some jurisdictions charge it on the pre-coupon price for manufacturer coupons, so there is a switch. A free-shipping threshold is measured against the discounted subtotal, which is how most of them work — and is the reason a bigger discount sometimes costs you more overall by dropping the order back under the threshold.
A coupon can never take a price below zero, so a $30 coupon on a $20 item is worth $20 and the rest is not refunded or carried over. The page reports that rather than showing a saving that does not exist.
FAQ
Is 20% off plus 10% off the same as 30% off?
No. The second discount is taken from the price the first one left, so the result is 28% off. Stacked percentages multiply rather than add, and the gap widens the more offers are stacked.
Does the order discounts are applied in change the price?
Only when a fixed-amount coupon is involved — and then yes, by the coupon amount times the percentage. A $20 coupon is worth the full $20 applied after a 25% discount, but only $15 applied before it. Percentages among themselves can be applied in any order.
How do I calculate a stacked discount?
Apply each offer to the running price rather than to the original. Multiply by (1 − rate) for each percentage, and subtract fixed amounts at the point they apply. This page does that and shows the price after every step.
Is tax charged before or after a discount?
Usually after, on the discounted price, which is why a discount reduces the tax as well. Manufacturer coupons are the common exception — several US states tax the pre-coupon price — so both are available here.
What happens if a coupon is worth more than the item?
Only as much of it as the price allows is used. The remainder is not refunded and does not carry to another item, and the page flags it when that happens.