What does “an extra 10% off” save?
A price tag says 20% off, and a second offer takes another 10% off the sale price. Starting from 100, the first reduction leaves 80. The second removes 8, leaving 72. You save 28 altogether, so the effective discount is 28%.
The useful question is which price each percentage applies to. This calculator assumes every new discount uses the amount left by the previous one. Use it to compare a sequence of percentage reductions with a single advertised rate, or to check the arithmetic behind an offer.
Final price tells you what remains to pay for the entered amount. Total savings tells you how much was removed. Effective discount turns that saving into one equivalent percentage of the Original price. Keeping those three results together helps you avoid confusing the amount saved with the amount still due.
Set up the discount sequence
Start before the first listed discount
Enter the Original price in one currency. If your starting price already includes a sale reduction, list only the further discounts. Entering that first reduction again would count it twice.
List the percentage reductions
Enter each rate in a Discount (%) row, in the order shown by the offer. Enter 20 for 20%, not 0.20. Add discount supports up to ten rows; remove an unused row or enter 0.
Compare the price and saving
Read Final price together with Total savings and Effective discount. Results update automatically. Check discounts highlights incomplete entries, while Reset example restores the 100 price with 20% and 10% reductions.
Original price accepts 0.01 through 1,000,000,000,000 with up to two decimal places. Each percentage accepts 0 through 100 with up to four decimal places. Use a decimal point and omit commas, currency signs, percent signs, and scientific notation. All money results use the starting currency, with a fixed two-decimal display rather than currency-specific formatting.
How successive discounts are calculated
A 20% discount leaves 80% of the current price. Written as a multiplier, that is 1 − 20 ÷ 100 = 0.80. Multiply the price by that remaining fraction, then repeat with the next percentage.
Price after a step = Previous price × (1 − Discount ÷ 100)
Final price = P × (1 − d₁ ÷ 100) × (1 − d₂ ÷ 100) × …
Total savings = Original price − Final price
Effective discount (%) = Total savings ÷ Original price × 100
P is the Original price. Each d is a discount percentage, and the multiplication continues once for every row. The effective discount expresses the combined saving as one percentage of P, so it gives you a common basis for comparing offers.
The calculator carries exact decimal values through all steps. Rounding is only for the displayed results. The remaining-price multipliers also show why adding the percentages would use the wrong base.
Worked example: 100 with 20% then 10% off
Think of an item priced at 100 in your currency. The first offer removes 20. The next offer is worth 10% of 80, which is 8 rather than 10.
After 20% off: 100 × 0.80 = 80
After another 10% off: 80 × 0.90 = 72
Savings: 100 − 72 = 28
Effective discount: 28 ÷ 100 × 100 = 28%
You would pay 72.00 before any extra charges. A single 30% discount on the same 100 price would leave 70.00, so it saves 2.00 more than this sequence. Compare the final amounts when the starting prices differ; a larger percentage alone does not establish the cheaper offer.
The difference between 28% and 30% is 2 percentage points. In this example it also equals 2.00 in money because the starting price is 100. Percentage points describe the gap between the rates; the price determines how much money that gap represents.
More examples to check your result
| Original price | Discounts | Final price | Effective discount |
|---|---|---|---|
| 200.00 | 25%, 20%, 10% | 108.00 | 46% |
| 19.99 | 15%, 10% | 15.29 | 23.5% |
| 80.00 | 50%, 50% | 20.00 | 75% |
For the three-discount example, 200 becomes 150, then 120, then 108. Total savings are 92.00. For the 19.99 item, the unrounded prices are 16.9915 and 15.29235. Its total saving is 4.69765, displayed as 4.70. Two half-price reductions leave one quarter of the original price, so they do not make an item free.
Rounding, order, and the checkout price
Reversing pure percentage discounts gives the same exact final price because the remaining fractions are multiplied together. However, each step’s saving changes. Keep the advertised order when you want the breakdown to match the sequence you are checking.
Displayed money rounds to the nearest hundredth, with halfway amounts rounded up. A positive amount below 0.01 is shown as <0.01 so it is not mistaken for exactly zero. Each table amount rounds independently, which can cause a small difference when you add the displayed savings yourself.
Consider a small price of 0.05 with two 10% discounts. The exact sequence is 0.05 × 0.90 = 0.045, then 0.045 × 0.90 = 0.0405. This calculator displays a Final price of 0.04 and an Effective discount of 19%. If a checkout instead rounds the remaining price half up to two decimals after every step, each 0.045 becomes 0.05 and its final amount stays 0.05. That is an illustration of a different rounding method, not a claim that every store uses it.
Effective discount rounds to two decimal places, with unnecessary zeros removed. Very small positive rates show <0.01%; rates just below 100% that would round to 100% show >99.99%. A displayed percentage is a summary, not the number used to calculate the price.
A 0% row changes nothing. A 100% row leaves zero, and later percentage reductions cannot reduce it further. Original price must be positive. Negative prices, negative discounts, and reductions above 100% are outside this calculator’s scope.
This result assumes the offers are allowed together and each percentage uses the remaining price. It does not check store eligibility, minimum spending, excluded items, fixed-amount coupons, tax, shipping, fees, or cashback. Check those terms before treating the result as your checkout total.
Check the offer’s calculation base
The word “stacked” does not by itself tell you how a store combines offers. A successive reduction uses the price left after the previous discount. Two reductions based on the same subtotal use a different calculation, even when both offers appear on the same order.
For a concrete platform example, Shopify’s calculation rules distinguish product discounts followed by order discounts from multiple percentage order discounts calculated on the same subtotal. Use this calculator only when the offer follows the successive method. Check the current store terms rather than assuming every pair of coupon codes behaves alike.
Before comparing offers, confirm that the starting price refers to the same item or eligible group of items. Check whether the displayed sale price already includes a reduction, whether further coupons can combine, and whether delivery or other charges change the amount due. The calculator explains the discount arithmetic; the retailer decides which offers apply.
Sources and calculation basis
The formula is derived from multiplying the fraction of the price that remains after each reduction. Fundamentals of Business Math: Discounts provides a reference for series discounts and their equivalent single rate.
Store combination rules are separate from that arithmetic. Shopify’s official discount-combination guide describes eligibility settings and different calculation bases. Its rules are specific to that platform; they are not a promise about every retailer.
Frequently asked questions
Is 20% off followed by 10% off the same as 30% off?
No. Successive discounts of 20% and 10% save 28% of the original price. The second rate uses the reduced price. If a store calculates both reductions from the same starting subtotal, that is a different method from the one used here.
Does the order of the percentages matter?
The exact final price is unchanged when you reverse pure percentage discounts on the same amount. The savings at each step change. Store rules, fixed-amount coupons, or rounding after each step can change that conclusion.
Which price should I enter?
Enter the price before the first discount you list. If you start with an already reduced sale price, enter only the additional discounts that still apply. All money amounts remain in the currency of that starting price.
Can I add a fixed-amount coupon?
No. Each row is a percentage. A coupon for 10 currency units is not necessarily 10% off, and its position in the sequence can affect the result. This calculator does not model fixed-amount coupons.
Does the final price include tax or shipping?
No. Final price covers only the successive percentage reductions you entered. Tax, shipping, fees, cashback, and promotion eligibility are outside this calculation.
Why might my receipt show a different amount?
A checkout may round after each reduction or apply different eligibility and combination rules. This calculator keeps exact decimal precision between steps. Displayed money rounds to two decimals, with positive amounts below 0.01 marked <0.01; these display values are not fed back into the calculation.
Can I enter zero or 100%?
Yes, for a discount. Zero leaves the current price unchanged; 100% reduces it to zero, so later percentage discounts save nothing more. The original price must be at least 0.01.
How many discounts can I enter?
Use one to ten discounts. Add discount creates a blank required row; remove unused rows or enter 0. Reset example restores a price of 100 with discounts of 20% and 10%.
Related calculators
- Percent Off Calculator — apply one percentage reduction to a price.
- Percentage Decrease Calculator — find the reduction rate when you already know both prices.
- Reverse Percentage Calculator — work back to an original amount from a percentage change.