Discount Calculator
Free discount calculator. Find the final price after a percent-off discount, the dollars saved, and the effective rate when stacking multiple discounts.
Quick answer
Final price = original × (1 − discount %). Stacked discounts compound — 20% off then 10% off is 28% off (not 30%), because the second discount applies to the already-reduced price.
Discount Calculator
Sale price
How it works
Discount amount = original price × (discount % / 100). Sale price = original − discount. Use this to confirm whether the "30% off!" sticker matches the price the cashier rings up.
When to use it
Black Friday, clearance racks, coupon stacking, or comparing two items where one is "20% off $50" and the other is "$45 flat" (the 20%-off one wins by $5).
Common mistakes
Compounding sequential discounts as if they were additive. "30% off then an extra 20% off" is NOT 50% off — it's 44% off (you pay 70% × 80% = 56% of original).
How the discount calculator works
A single percent-off discount is straightforward: subtract the discount percentage from 100, divide by 100, and multiply by the original price. For stacked discounts, multiply the surviving fraction of each discount: a 20%-off coupon combined with a 10%-off member discount keeps 80% × 90% = 72% of the price, which is a 28% effective discount, not 30%. Most retail systems apply the largest discount first and the smallest last — this rarely matters for the math but can affect tax calculation if the discount is line-item rather than order-level.
When to use it
Comparing 'X% off' vs. '$Y off' offers when they aren't apples-to-apples. Computing the real cost-per-unit when buying in promotional bundles. Stacking coupon codes on top of sale prices. Decoding 'BOGO 50% off' (which is actually 25% off the pair) vs. 'BOGO free' (50% off the pair) — bigger numbers don't always mean a bigger discount.
Common mistakes
- Adding stacked percentages. 20% + 10% does not equal 30%. It equals 28%. Always multiply the surviving fractions.
- Confusing markdown with markup. A 50% markdown drops a $100 item to $50. A 50% markup raises a $100 cost to $150. The percentages refer to different baselines.
- Falling for anchored discounts. 'Was $300, now $150!' is only a real 50% discount if the $300 was a real selling price. Many retailers anchor against an inflated MSRP that nothing ever sold at.
Frequently asked questions
How do I calculate a percentage off?
Multiply the original price by (1 minus the discount as a decimal). A 25% discount on $80 is $80 × 0.75 = $60. The savings is $80 × 0.25 = $20.
How do you combine multiple discounts?
Multiply the surviving fractions. A 20% coupon + 10% member discount keeps 0.80 × 0.90 = 0.72 of the price. So the combined discount is 28%, not 30%.
Is BOGO 50% off the same as a 50% discount?
No. BOGO 50% off means the second item is half price, so on two equal-priced items you save 25% of the pair's total. BOGO free is a 50% discount on the pair. Always check the math when retailers advertise 'BOGO' offers.