Discount Percent:
25.00%
Discount Amount:
$20.00
Table of Contents
How much did the price actually drop?
Enter the original (regular) price and the sale price — the calculator returns both the percentage discount and the dollar savings. Useful for shoppers verifying advertised deals and for retailers setting markdowns.
How the discount calculation works
Working backwards from two prices to the percentage discount uses one short formula:
Discount% = (Original Price − Sale Price) ÷ Original Price × 100
- Original Price — the regular price before any reduction.
- Sale Price — the actual price being charged at the till.
- Discount Amount = Original Price − Sale Price (the dollar saving).
- Discount% = the saving expressed as a percentage of the original.
Worked example using the calculator's default values ($80 original, $60 sale):
- Discount Amount = $80 − $60 = $20
- Discount% = $20 ÷ $80 × 100 = 25.00%
The reverse calculation — finding the sale price when you know the discount percentage — is just Sale Price = Original × (1 − discount%/100). At 25% off $80: $80 × 0.75 = $60.
Stacking discounts: the "extra 20% off" trap
Retailers regularly advertise "30% off, plus an extra 20% off at checkout" — and shoppers (and sometimes the cashier) assume that totals to 50% off. It does not. Each successive discount applies to the already-reduced price, not the original.
Final Price = Original × (1 − d1) × (1 − d2) × …
| Advertised stack | If added together | Actual total discount | $100 becomes |
|---|---|---|---|
| 20% + 10% | 30% | 28% | $72.00 |
| 30% + 20% | 50% | 44% | $56.00 |
| 40% + 20% | 60% | 52% | $48.00 |
| 50% + 25% | 75% | 62.5% | $37.50 |
| 70% + 30% | 100% ("free") | 79% | $21.00 |
The order of stacking does not matter mathematically — 30% then 20% gives the same result as 20% then 30%. But order can matter for sales tax: in some jurisdictions, store coupons reduce taxable amount but manufacturer coupons don't, so applying them in different orders can change what's taxed.
Setting a markdown that protects margin
Discounts are a margin lever, not a free promotional tool. A 30% discount on an item with a 40% gross margin leaves only 10%. The same discount on an item with a 25% gross margin sells at a loss. Before approving a markdown, work backwards from your minimum acceptable margin:
Minimum Sale Price = Unit Cost ÷ (1 − Target Margin)
- Unit cost $40, target margin 25%: minimum price = $40 ÷ 0.75 = $53.33.
- If regular price is $80, the maximum discount that preserves 25% margin is ($80 − $53.33) ÷ $80 = 33% off.
- Going to 40% or 50% off — common "clearance" depths — sells below margin and may sell below cost.
For clearance, that may be acceptable to move dead stock; for routine sale events, it isn't. Many small retailers discount on instinct without doing this math — and then wonder why a strong sales month doesn't translate to a strong profit month.
Reference pricing and FTC rules on "original" prices
The original price isn't just a math input — it's a psychological anchor. An item priced at $80 with "25% off — now $60" consistently outperforms the same item simply priced at $60. The original price makes the sale price feel like a gain rather than a baseline.
But the Federal Trade Commission's Guides Against Deceptive Pricing require that an advertised "regular" or "original" price actually represents a bona fide previous selling price — not an inflated reference designed to make the sale look bigger. Posting an item at a fictional "was $200" price for a few hours before discounting it to $99 (the price it always actually sold at) is considered deceptive. Several major retailers have settled FTC and state actions on exactly this practice.
Limitations of this calculator
- Single-step discount only. For stacked discounts, multiply (1 − d) factors using the formula above, or apply each discount one at a time.
- Pre-tax. Sales tax is calculated separately, usually on the discounted price (with state-by-state exceptions for manufacturer coupons).
- No quantity or bundle handling. For BOGO and multi-buy deals, total the actual amounts paid and divide into the total original price.
- No assessment of whether the "original" price is real. A 70% discount off a fictional anchor price is still misleading even though the math here computes a clean 70%.
Sources & references
- FTC — Guides Against Deceptive Pricing (16 CFR Part 233) — the authoritative US standard for what can be advertised as a "regular" or "original" price.
- FTC Consumer Advice — How To Shop Sales — consumer-facing guidance on evaluating advertised discounts.
- US Small Business Administration — Manage Your Finances — pricing, margin, and markdown fundamentals for small businesses.
FAQs
No — it works out to 44% off, not 50%. The second discount applies to the already-reduced price, not the original. On a $100 item: 30% off brings it to $70, then 20% off $70 brings it to $56. That is a total discount of $44, or 44%. The formula for stacked percentage discounts is: final price = original × (1 − d1) × (1 − d2). Stacking discounts always produces a smaller total than adding the percentages.
Retail psychology research consistently shows that an $100 item marked "25% off — now $75" outperforms the same item simply priced at $75. The original price serves as an anchor that makes the sale price feel like a gain. The effect is strongest when the discount is meaningful (typically 20%+) and the original price was genuinely the previous selling price — the FTC requires that "original" or "regular" prices be bona fide, not fictional reference points.
Work backwards from the margin you need. If unit cost is $40 and you want at least a 25% gross margin, your minimum selling price is $40 ÷ (1 − 0.25) = $53.33. The maximum discount off your regular $80 price that still preserves that margin is ($80 − $53.33) ÷ $80 = 33% off. Any deeper discount cuts into margin. Use this calculation before approving a sale — many retailers discount so aggressively they sell at a loss.
They're often used interchangeably but have distinct meanings in retail. A discount is a temporary price reduction at the point of sale — the original price still applies to inventory not on sale. A markdown is a permanent reduction of the listed price, typically because the item isn't selling at the original price. Markdowns reduce inventory value on the balance sheet; discounts don't. End-of-season clearance is usually a markdown; a flash sale or coupon is usually a discount.
In nearly all US states, sales tax is calculated on the final discounted price — the actual amount the customer pays. Store-issued discounts (a coupon from the store, a percentage-off promotion) reduce the taxable amount. Manufacturer coupons are treated differently in some states because the store ultimately receives full price (reimbursed by the manufacturer), so the original price is taxed. Verify your state's rules — this is a common source of overpayment by consumers and undercharging by retailers.