Percent Off Calculator

Quick percent-off reference

How stacked discounts actually work

Discount stacking is the source of more retail confusion than almost any other math. The intuitive (wrong) answer: 20% off plus 10% off equals 30% off. The actual answer: it's 28% off. Each discount applies to the previous result, not the original. On a $100 item: $100 × 0.80 = $80 after the first 20%. Then $80 × 0.90 = $72. Total savings $28, or 28% off the original.

The math always rounds in the retailer's favor. A "30% off plus 20% off" deal sounds like 50% off, it's actually 44%. "Half off plus an additional 25% off" sounds like 75% off, it's 62.5%. The bigger the headline numbers and the more stacked layers, the wider the gap between perceived and real savings.

Formula for any two stacked percentages: effective discount = 1 − (1 − d1) × (1 − d2). For three: 1 − (1 − d1) × (1 − d2) × (1 − d3). The order doesn't matter, 20% then 10% gives the same final price as 10% then 20%. But order can matter for store policy: many retailers apply the largest discount first or stack loyalty coupons in a specific order, and some only allow stacking certain promo types together.

Worked shopping scenarios

Department store stack: A $240 coat marked 40% off (now $144), then 20% off the sale price (now $115.20), then a 15% credit card coupon ($98.92). Effective discount: 58.8%, not the headline-sum of 75%. Add 8% sales tax: $106.83 total out the door.

BOGO 50% off: Two items at $50 each. The "second 50% off" deal really means 25% off the combined order ($100 → $75). It feels like half off but only one item gets the discount.

Reverse calculation, finding the sticker price: You paid $63 after a 30% off sale and 10% loyalty stack. Original = 63 / (0.70 × 0.90) = 63 / 0.63 = $100. Useful when comparing prices to non-discounted competitors or verifying a "regular price" claim.

Discount tricks to watch for

• Inflated "regular price": A common practice where the "original" price was set just before the sale specifically to be discounted. Compare to historical actual prices via tools like CamelCamelCamel for Amazon or Honey's price history.
• "Up to 75% off" signage: The 75% applies to a few clearance items deep in the back. Most of the rack might be 20-30% off. Always check individual price tags.
• Tax on pre-discount price (rare but happens): In most US states, sales tax applies to the after-discount price. A few promotional contexts (manufacturer rebates, certain coupons) are taxed on the pre-discount amount. Read your receipt.
• Free shipping thresholds: A 25% off coupon that brings you under the free-shipping threshold can cost more than it saves once shipping is added. Always compare total-cost-to-door.
• Restocking fees on returns: Deep-discounted "final sale" items often can't be returned. Factor in the option value of a return if you might change your mind.

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