This discount calculator shows what you actually pay for one item after one or two percentage discounts, and how much you save in dollars. Enter the original price, the first discount, an optional second discount and an optional assumed sales-tax rate.
The main limit: it cannot tell you whether coupons stack or whether the “original” price was genuine. Two discounts in a row multiply; 20% off then 10% off is 28% off before cent rounding, not 30%.
Discount calculator
This calculator runs in your browser. This calculator’s code does not send, save, or track your entries. All dollar amounts are USD.
Optional example: Inputs start blank. Load example fills hypothetical figures without calculating. Examples are not current rates, quotes, or recommendations.
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What should you enter besides the headline percentage?
Use the original price for one item and enter the first discount. Enter 0 for a second discount you do not need, or for tax when you only want the pre-tax result. The fields still need a number even when a step does not apply to you.
The second discount is applied to the amount left after the first. The tool does not check whether a coupon stacks, whether an item is excluded or whether an order meets a minimum-spend requirement. Confirm those terms with the seller before treating two percentages as an available offer.
All defaults and examples are hypothetical, not retailer offers or current tax rates.
How do you calculate a discounted price with two discounts?
For original price P, first discount a% and second discount b%:
- Discounted price before rounding = P × (1 − a/100) × (1 − b/100).
- Combined percentage before rounding = 100 × [1 − (1 − a/100) × (1 − b/100)].
- Item savings = original price − final discounted item price rounded to cents.
- Effective item discount = item savings ÷ original price × 100.
- Paid price = cent-rounded discounted price + separately cent-rounded assumed tax.
The calculator rounds the discounted item price once, at the end. A retailer that rounds after each discount step could land one cent differently.
How the calculator handles inputs and rounding
Enter the original price with no more than two decimals and percentages with no more than four. The calculation keeps exact decimal factors until the final discounted item price is rounded to cents.
The displayed first-discount price is informational only and is not fed back as a rounded intermediate. Tax is then calculated on the selected basis and rounded separately. Half-cent ties round up, so the paid-price and savings rows reconcile.
A 0% discount changes nothing. A 100% discount makes the item price zero, even with another sequential discount, but the before-discount tax assumption can still leave a nonzero tax amount. At a $0 original price, the percentage saved is undefined, and the tool labels it instead of showing a misleading number.
Price is supported up to $1,000,000 and rates from 0% to 100%. The calculation module does not store or transmit entered values.
Is 20% off then 10% off better than 30% off?
Inputs. A hypothetical $120 item gets 20% off, then 10% off, with an assumed 8% sales tax applied after the discounts.
Formula and result. The first discount leaves $96. The second removes $9.60, leaving $86.40 before tax. Item savings are $33.60, or 28% of $120. Tax is $86.40 × 0.08 = $6.912, rounded to $6.91, so the paid price is $93.31.
Without any discount, the same item would cost $120 + $9.60 tax = $129.60. Total savings against that comparison are $36.29, which includes the lower tax. That is a different measure from the $33.60 item discount.
| Offer | Item price | Item savings | Paid including tax |
|---|---|---|---|
| No discount | $120.00 | $0.00 | $129.60 |
| 20% only | $96.00 | $24.00 | $103.68 |
| 20%, then 10% | $86.40 | $33.60 | $93.31 |
| 30% only | $84.00 | $36.00 | $90.72 |
What to check. The single 30% discount is cheaper here. Compare final prices for the same item and terms rather than adding advertised percentages.
How much can cent rounding and tax basis change the price?
A hypothetical $19.99 item with 15% off followed by 10% off gives $19.99 × 0.85 × 0.90 = $15.29235. Round once to $15.29. Savings are $4.70. The combined discount is 23.5% before rounding, while savings divided by the original price is about 23.5118% after cent rounding.
At an assumed 7.25% rate applied after the discounts, tax is $15.29 × 0.0725 = $1.108525, rounded to $1.11. The paid price is $16.40.
If you select the original price as the tax basis instead, tax is $19.99 × 0.0725 = $1.449275, rounded to $1.45, for a $16.74 paid price. These are alternative assumptions, not a statement that either treatment applies to your purchase.
Is the advertised saving a real saving?
The FTC’s online shopping guidance suggests learning the total cost, including shipping, handling, delivery, taxes and other fees, and reading the terms of the advertised deal. This tool includes only the entered item price and assumed tax, so add excluded charges separately. The same page suggests double-checking return policies for sale items.
The FTC’s former-price comparison guide distinguishes a genuine prior price from an artificially inflated comparison price. The calculator cannot verify price history, and a large percentage off an unreliable reference price does not establish a bargain.
When does this discount calculator not fit?
- You are buying several items or a bundle. It models one item; quantity offers, buy-one-get-one deals and cart-level minimums are not included.
- Shipping, fees or rebates change the total. Shipping, fees, rebates, rewards and merchant-specific eligibility are excluded.
- You need the real tax on a purchase. Tax mode is your assumption, not a jurisdiction lookup or tax advice.
- The choice repeats over time. For recurring costs, see annual versus monthly subscription costs. For a membership fee justified by repeated shopping savings, use the warehouse membership break-even guide. To compare package sizes, use the grocery unit price calculator.
Quick decision checklist
- Check whether the second coupon actually stacks on the sale price.
- Compare final paid prices, not the sum of advertised percentages.
- Add shipping, fees and any tax you expect before comparing sellers.
- Ask whether the “was” price reflects a price the item actually sold for.
- Read the return policy for sale items before you buy.
Sources and review
- FTC Consumer Advice, Online Shopping: comparing total cost, reading deal terms and checking sale-item return policies.
- 16 CFR 233.1, Former price comparisons (eCFR): genuine versus fictitious former prices. eCFR describes its text as authoritative but unofficial.
Sources checked September 28, 2026. They support the shopping and comparison-price cautions, not the sequential-discount arithmetic or any sales-tax rule; the examples, precision limits and rounding convention are this tool’s own model.
Prepared with AI-assisted research, drafting, and calculation checks. Not independently reviewed by a human financial professional.
