How do I calculate a discount?

Multiply the original price by the discount percentage as a decimal to get the amount saved, and subtract it from the original price. For $80 with 25% off, the saving is $80 × 0.25 = $20 and the sale price is $60.

Why are two discounts worth less than their sum?

The second discount applies to the price after the first one, not to the original. 30% off followed by an extra 20% off is 1 − 0.70 × 0.80 = 44% off in total, not 50%. The order does not change the result.

How do I find the discount percentage from two prices?

Subtract the sale price from the original price, divide by the original price and multiply by 100. A jacket reduced from $120 to $90 is $30 ÷ $120 = 25% off.

How do I find the original price before a discount?

Divide the sale price by one minus the discount as a decimal. If you paid $75 after 25% off, the original price was $75 ÷ 0.75 = $100. Do not add 25% to $75, because the discount was taken from the larger price.

Is sales tax charged before or after the discount?

For most store discounts, tax is charged on the price after the discount, so you pay less tax. Manufacturer coupons and some rebates are taxed differently in some states, so check the rules where you buy.

What increase brings a discounted price back to the original?

More than the discount itself. After 20% off you need a 25% increase to return to the original price, after 50% off you need 100%. That is because the increase is applied to the smaller price.

📊 Business & Ecommerce

Discount Calculator · Sale Price, Percent Off and Stacked Discounts

A discount looks simple, but the arithmetic trips people up: a 30% discount followed by an extra 20% off is not 50% off, a sale price does not tell you the percentage unless you know the original, and tax is charged on the price after the discount, not before. This calculator handles the three questions shoppers and sellers ask most often.

Use it to find the sale price when you know the original price and the percent off, optionally with a second discount stacked on top, a quantity and sales tax. Switch to the second mode to find the discount percentage when you know the original and the sale price, which also tells you when a so-called sale is really a price increase. Use the third mode to work backwards from what you paid and the discount to the original price.

For sellers, the same math shows what a promotion really costs: a discount comes straight out of your margin, so a 10% discount on a product with a 20% margin cuts the profit per sale in half. Stacked discounts multiply rather than add, because the second percentage applies to the already reduced price, which is why two coupons are always worth less than their sum.

Detailed Breakdown

4 metrics

PRIMARY RESULT

$60.00

Sale Price per Item

You Save per Item

$20.00

Total Discount

25.0%

Total to Pay

$60.00

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exploreReal-World Scenarios

When to Use This Calculator

Everyday financial situations where this tool gives you fast, accurate clarity:

🛍️

Check a Sale Price

Find what an item really costs after a percent off, including sales tax and the quantity you buy.

🏷️

Stack Coupons

See the true total discount when a second coupon or promotion applies to the sale price.

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Spot a Fake Sale

Work out the actual discount between two prices and see when the "sale" is a price increase.

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Plan a Promotion

Find the original price behind a discount and see how much a promotion takes from your price.

Calculation Formula

Standard Method

Sale Price = Original Price × (1 − Discount %) With a second discount: Sale Price = Original Price × (1 − Discount 1) × (1 − Discount 2) Total Discount = 1 − (1 − Discount 1) × (1 − Discount 2) You Save = Original Price − Sale Price Sales Tax = Sale Price × Quantity × Tax Rate; Total to Pay = Sale Price × Quantity + Sales Tax Find the discount from two prices: Discount % = (Original − Sale) ÷ Original × 100. A negative result means the price went up. Find the original price: Original = Sale Price ÷ (1 − Discount %). Discounts are limited to 0% through 100%. Sales tax is applied to the discounted price, as most states do for store discounts; manufacturer coupons and rebates can be treated differently depending on the state.

Benchmark Example:

A jacket with an original price of $80 and a 25% discount: • Sale price: $80 × (1 − 0.25) = $60.00 • You save: $20.00 • With 8% sales tax: $60.00 + $4.80 = $64.80 • Buying three: $180.00 plus $14.40 of tax = $194.40, saving $60.00 in total Stacked discounts: $100 with 30% off, then an extra 20% off the sale price, gives $100 × 0.70 × 0.80 = $56.00, a total discount of 44%, not 50%. Working backwards: an item that cost $90 after being reduced from $120 had a discount of ($120 − $90) ÷ $120 = 25%. And an item paid at $75 after 25% off had an original price of $75 ÷ 0.75 = $100.

Frequently Asked Questions

6 answers

Applicable Laws & Regulatory Standards

Federal Trade Commission

Official Legal Reference

FTC Guides Against Deceptive Pricing — 16 CFR Part 233

Say that a "regular" or "original" price used to advertise a sale must be a price the seller genuinely charged, so a discount cannot be measured against a price that was never really offered.

FTC Act § 5 — 15 U.S.C. § 45 (Unfair or Deceptive Acts or Practices)

Prohibits deceptive advertising, including false claims about savings, sales and limited-time offers.

FTC Guide Concerning Use of the Word 'Free' and Similar Representations — 16 CFR Part 251

Requires that an offer described as free, such as buy one get one free, be truly free of added cost and that its conditions be clearly disclosed.

Legal citations and statutes are provided for consumer transparency, analytical validation, and educational reference under U.S. consumer financial regulations. This tool is not a substitute for formal legal, accounting, or tax counsel.

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