A store advertises 20% off, you have a 10% coupon, and it’s easy to assume you’re getting 30% off the original price. You’re not. Here’s the actual math, and why the real number is always a bit less than the sum of the two percentages.<\/p>\n
Discounts stack multiplicatively, not additively. The second discount applies to the already-reduced price from the first one, not to the original price. On a $100 item: 20% off brings it to $80. Take another 10% off that $80, not the original $100, and you get $72. Your total savings is $28 on a $100 item, a 28% effective discount, not 30%.<\/p>\n
The gap between the two numbers grows as the discounts get bigger. Two 25% discounts stacked don’t make 50% off, they make 43.75% off: $100 becomes $75 after the first discount, then $56.25 after the second, a combined savings of $43.75, not $50.<\/p>\n
Take a $120 item with a 30% storewide sale plus an extra 15% coupon on top. 30% off $120 is $84. Take 15% off that $84, and you land at $71.40. Total savings: $48.60, an effective discount of 40.5%, meaningfully less than the 45% a straight sum would suggest, though still a substantial saving.<\/p>\n
Retailers aren’t hiding anything shady here, multiplicative stacking is just how percentage discounts mathematically compound, the same underlying math as compound interest, just working in your favor as a shopper instead of against you as a borrower. The practical issue is that most people mentally add percentages together out of habit, which means the number in your head going into checkout is usually a little higher than what you’ll actually see subtracted.<\/p>\n
This matters most when you’re comparing two different stacking offers against each other. “20% off plus an extra 10%” and “flat 28% off” sound like different deals, one sounds bigger, but they’re mathematically identical. Knowing this stops you from picking a worse-sounding but actually-equal or better flat discount over a stacked one that sounds bigger.<\/p>\n
Rather than multiplying percentages by hand or guessing, our Discount Calculator<\/a> has a dedicated mode for exactly this: enter up to three stacked discounts, and it calculates your true effective percentage automatically, along with a plain-language note like “your effective discount is 28%, not 30%” whenever the stacked total differs from what a naive sum would suggest.<\/p>\n If you’re trying to figure out the reverse, what a price was before a discount was applied, our Reverse Percentage Calculator<\/a> handles that specific direction instead.<\/p>\n No. Stacked discounts multiply against the already-reduced price, not the original price, so the combined discount is always slightly less than the sum of the individual percentages. 20% plus 10% comes to 28% off, not 30%.<\/p>\n Apply the first discount to the original price, then apply the second discount to that new, already-reduced price, not the original. Or use a discount calculator<\/a> that supports multiple stacked discounts directly.<\/p>\n It’s the same multiplicative principle applied to any number of successive percentage reductions, a storewide sale plus a coupon plus a loyalty discount, for example. Each additional discount applies to the price left after the previous one, so the effective total discount is always a bit below the simple sum of all the percentages involved.<\/p>\n It depends on the two rates, but it’s always less than their sum. For two discounts of a% and b%, the combined discount works out to a + b \u2212 (a\u00d7b\/100) percent. For 20% and 10%, that’s 20 + 10 \u2212 2 = 28%.<\/p>\n See your real effective discount instantly, for one discount or several stacked together, with the Discount Calculator<\/a>.<\/strong><\/p>\n A store advertises 20% off, you have a 10% coupon, and it’s easy to assume you’re getting 30% off the original price. You’re not. Here’s the…<\/p>\n","protected":false},"author":1,"featured_media":980,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[15],"tags":[],"class_list":["post-115","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-percentages-shopping-math"],"_links":{"self":[{"href":"https:\/\/thenesttools.com\/blog\/wp-json\/wp\/v2\/posts\/115","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/thenesttools.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/thenesttools.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/thenesttools.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/thenesttools.com\/blog\/wp-json\/wp\/v2\/comments?post=115"}],"version-history":[{"count":2,"href":"https:\/\/thenesttools.com\/blog\/wp-json\/wp\/v2\/posts\/115\/revisions"}],"predecessor-version":[{"id":191,"href":"https:\/\/thenesttools.com\/blog\/wp-json\/wp\/v2\/posts\/115\/revisions\/191"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/thenesttools.com\/blog\/wp-json\/wp\/v2\/media\/980"}],"wp:attachment":[{"href":"https:\/\/thenesttools.com\/blog\/wp-json\/wp\/v2\/media?parent=115"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/thenesttools.com\/blog\/wp-json\/wp\/v2\/categories?post=115"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/thenesttools.com\/blog\/wp-json\/wp\/v2\/tags?post=115"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Frequently Asked Questions<\/h2>\n
Do discounts add up when you stack them?<\/h3>\n
How do I calculate a double discount?<\/h3>\n
What is coupon stacking math, exactly?<\/h3>\n
What’s the effective discount percentage for two stacked discounts?<\/h3>\n
Related Reading<\/h2>\n
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