π·οΈ Triple Discount Calculator
Why stacked discounts multiply, not add.
Final price
Estimates for planning only, not financial advice.
A $200 item with successive discounts of 20, 10, and 5 percent costs $136.80, not $130. The effective discount is 31.6 percent, not 35 percent. Each discount applies to the already-reduced price, which is exactly why retailers love stacking them: it sounds bigger than it is.
How to Use This Calculator
Enter the original price and the three discount percentages in the order they apply. The calculator gives the final price, total savings, and the true effective discount rate.
Enter the pre-discount price. Use the price before any of the three discounts.
Enter each discount as a percent. Typical stacks: trade discount, then promotional, then coupon.
Compare the effective rate against the naive sum to see the retailer's sleight of hand.
The Formula
Successive discounts multiply because each one applies to a smaller base: the 10 percent comes off the $160 left after the 20 percent, not off the original $200. Order does not matter (multiplication commutes), which is convenient because stores rarely tell you the application order. The gap between the naive sum and the effective rate grows with the discounts: 10+10+10 sounds like 30 percent but is really 27.1 percent.
Worked Example
$200, discounts 20, 10, 5 percent. After 20 percent: 200 x 0.80 = $160. After 10 percent: 160 x 0.90 = $144. After 5 percent: 144 x 0.95 = $136.80. Savings: $63.20. Effective discount: 63.20 / 200 = 31.6 percent versus the naive 35 percent. The retailer advertised three discounts totaling "35 percent off" and delivered 31.6 percent; the 3.4-point gap is pure margin.
Where Triple Discounts Appear
| Context | Typical stack |
|---|---|
| Wholesale / trade | Trade 20% + volume 10% + prompt-payment 2% |
| Retail promos | Sale 30% + coupon 20% + cardholder 10% |
| Clearance | Markdown 50% + extra 25% + coupon 15% |
| B2B software | List discount + multi-year + prepay |
Trade discounts are the classic home of this math: a distributor quote of "20/10/5" is industry shorthand for exactly this calculation. In B2B, the stack often hides in the quote as separate line items precisely because the effective rate is hard to compute mentally, which is now your advantage.
Single Equivalent Discount
Vendors sometimes ask for "the single equivalent" of a discount series. That is just the effective rate: 20/10/5 = 31.6 percent single equivalent. Negotiate in single-equivalent terms and the fog lifts: a competing quote of a flat 33 percent off beats the 20/10/5 stack even though it "sounds" smaller. Always convert stacks to single equivalents before comparing quotes, whether for inventory, software (see our contract value calculator), or anything else.
The Psychology
Stacked discounts exploit our additive intuition: 20+10+5 feels like 35. Retailers know the effective rate is lower and price accordingly. The defense is this calculator and one habit: never compare discount stacks by their face percentages. Convert to final price or single-equivalent rate, then decide. A "70 percent off clearance plus extra 20 percent" is 76 percent off, not 90, still great, but not what the sign implies.
Procurement Tactic: Demand the Single Equivalent
Professional buyers neutralize discount stacks with one sentence: "Please quote your best single equivalent discount." It forces the vendor to do the multiplication they were hoping you would not do, and it makes competing quotes comparable instantly. A supplier offering 25/10/5 (single equivalent 36.25 percent) against one offering a flat 35 percent: the stack wins, but only by 1.25 points, not the 5 points the face percentages suggest.
Watch for the stack-and-switch: vendors who advertise a rich series but apply each discount to a different base, or who quietly raise the list price before discounting. Always anchor on the final extended price versus your last paid price, not on the discount percentages. And negotiate the series itself: converting 20/10/5 into 25/10 (single equivalent 32.5 percent) beats converting it into 20/15 (32 percent), a comparison you can only make once everything is in single-equivalent terms.
One Number Beats Three
Triple discounts persist because "20/10/5" sounds bigger than "32.8% off," and buyers anchor on the first number they hear. The defense is arithmetic: convert every discount chain to its single equivalent before comparing offers, because a "30/10" (37%) beats a "25/15" (36.25%) despite the smaller headline. Suppliers count on buyers skipping this step; procurement teams that never skip it save real money.
The same math governs stacked promotions in retail: a 20-percent-off sale plus a 10-percent coupon is 28 percent off, not 30. Consumers who convert chains instinctively become immune to the most common pricing illusion in commerce. Whether you are buying inventory or a television, reduce the chain to one number first. The single equivalent is the only discount that matters.
Memorize the shortcut: multiply the complements. For 20/10/5, compute 0.80 x 0.90 x 0.95 = 0.684, so the single equivalent is 31.6 percent off. Ten seconds of arithmetic beats any salesman's patter.
Estimates for planning only, not financial advice.
Frequently Asked Questions
How do you calculate triple discount?
Multiply the keep-fractions: final = price x (1-d1) x (1-d2) x (1-d3). For $200 with 20%, 10%, 5%: 200 x 0.80 x 0.90 x 0.95 = $136.80. Each discount applies to the already-discounted price, not the original. Work it stepwise on paper the first time: $160 after the first cut, $144 after the second, $136.80 after the third.
Is 20% + 10% + 5% the same as 35% off?
No. Successive discounts multiply, giving an effective 31.6% off ($136.80 on $200 vs $130). The naive sum overstates the deal; the gap widens as discounts grow. Always compute the effective rate. Retailers count on additive intuition: three discounts that sound like 35% deliver 31.6%, and the 3.4-point gap is pure margin.
Does the order of discounts matter?
No. Multiplication commutes, so 20/10/5 gives the same final price as 5/10/20. Stores rarely disclose the application order because it makes no difference to the total. This is convenient: you never need to ask which discount applies first, since the arithmetic cannot tell the difference either.
What is a single equivalent discount?
One discount equal to the whole series: 1 minus the product of the keep-fractions. 20/10/5 = 31.6% single equivalent. Use it to compare a stacked quote against a flat-discount quote fairly. A flat 33% beats the 20/10/5 stack even though it sounds smaller; single equivalents strip away the framing.
What does 20/10/5 mean in trade quotes?
Industry shorthand for three successive discounts of 20%, 10%, and 5%, common in wholesale and distribution. The single equivalent is 31.6% off list. Distributors quote this way partly because the true rate is hard to compute mentally. When you see 20/10/5 on a quote, read it as 'about 32% off' and negotiate from there.
How do coupons stack with sale prices?
Usually multiplicatively: a 20% coupon on a 30%-off sale gives 0.70 x 0.80 = 44% off, not 50%. Some coupons apply to the original price instead; read the fine print, since that version is the more generous one. Manufacturer coupons at the register sometimes come off the pre-sale price, which is why they can beat store coupons of the same face value.
Can stacked discounts exceed 100%?
No. Each keep-fraction is positive, so the product stays positive and the effective discount stays under 100%. Even 90/90/90 leaves 0.1% of the price. You cannot be paid to take the item through discounts alone. If a deal ever implies more than 100% off, someone mislabeled a rebate as a discount.
Do taxes apply before or after discounts?
After, in almost all US states: sales tax applies to the final discounted price. That is a small extra win on stacked deals. A few states tax the pre-coupon price on manufacturer coupons, so check local rules. On a big-ticket stacked purchase, the tax-on-discounted-price rule can save more than the smallest discount in the stack.
Why do stores stack discounts instead of one big one?
Psychology and margin. Three discounts feel larger than their effective rate (additive intuition), let the store advertise bigger numbers, and preserve flexibility to drop one layer. The effective rate is what matters; compute it. It also segments customers: only price-sensitive shoppers stack all three, so the store price-discriminates without a loyalty card.
How do I compare two different discount stacks?
Convert each to its final price or single-equivalent rate, then compare. A flat 33% beats 20/10/5 (31.6%); 25/15 beats 30/5 (36.25% vs 33.5%). Never compare by face percentages. For B2B quotes, ask each vendor for their single equivalent in writing; the one who hesitates is telling you something.