How to Calculate a Discount
A discount reduces the original price of an item by a set amount. The reduction can be expressed as a percentage of the original price ("25% off") or as a fixed dollar amount ("$10 off"). This calculator works with both, and it can solve in any direction - find the sale price from a discount, find the discount from a sale price, or find the original price before the markdown.
For a percentage discount, the discount amount and sale price are calculated like this:
Discount Amount = Original Price × Discount % ÷ 100
Sale Price = Original Price - Discount Amount
For an original price of $80 at 25% off:
- Discount Amount = $80 × 25 ÷ 100 = $20
- Sale Price = $80 - $20 = $60
To work the other way - find the original price when only the sale price and discount percent are known - use the reverse formula:
Original Price = Sale Price ÷ (1 - Discount % ÷ 100)
For a sale price of $60 at 25% off:
- Original Price = $60 ÷ (1 - 0.25) = $60 ÷ 0.75 = $80
For a fixed-amount discount the math is direct subtraction - no percentage needed:
Sale Price = Original Price - Discount Amount
An original price of $80 with a $15 off coupon gives a sale price of $65.
The choice between percentage and fixed-amount discount depends on how the offer is stated. Percentage discounts scale with the price - 20% off saves more on expensive items than on cheap ones. Fixed-amount discounts ("$10 off any purchase", "$20 coupon") save the same dollar amount regardless of price, so they represent a larger relative saving on cheaper items. The calculator's discount field accepts either type through a % / $ switcher.
Stacked Discounts
A stacked discount is when two or more discounts are applied to the same item one after another - for example, "20% off, plus an extra 10% off at checkout". Each new discount applies to the already-reduced price, not the original. Because of this, stacked discounts do not add up the way they look: 20% + 10% is not 30% off.
The combined discount for two stacked percentages is calculated like this:
Combined Discount = 1 - (1 - D1 ÷ 100) × (1 - D2 ÷ 100)
For an original price of $100 with 20% off then 10% off:
- After 20% off: $100 × 0.80 = $80
- After extra 10% off: $80 × 0.90 = $72
- Total savings: $100 - $72 = $28 (28% off, not 30%)
The combined discount is always slightly less than the sum of the individual discounts. The bigger the first discount, the wider the gap. Here are common stack combinations and their real combined discount:
| First Discount |
Second Discount |
Combined |
| 10% |
10% |
19% |
| 20% |
10% |
28% |
| 20% |
20% |
36% |
| 25% |
10% |
32.5% |
| 30% |
15% |
40.5% |
| 50% |
25% |
62.5% |
The calculator above does not have a built-in stacked-discount mode yet. To find a stacked result, apply the discounts one at a time: enter the original price and the first discount to get the intermediate sale price, then re-enter that sale price as a new "original price" with the second discount. The order of the two discounts does not matter - the combined result is the same.
Using This Calculator
Beyond entering the basic values, the calculator has several features that make discount math faster and easier to share. Here is what each does and when to use it.
Discount type switcher
The % / $ selector next to the Discount field switches between percentage and fixed-amount mode. In % mode the discount is read as a percent of the original price ("25% off"); in $ mode it is read as a flat amount in the chosen currency ("$15 off"). Switching the type clears the Discount field so the new value is interpreted correctly. Use this to model coupon-style offers ($10 off any purchase) without doing percent math yourself.
Discount comparison
The comparison table on the right shows what the sale price and savings would be at several common discount percentages (5%, 10%, 15%, ..., up to 75%) for the original price you entered. It helps you see at a glance how much a deeper or shallower discount would change the result - useful for comparing competing offers or evaluating "how much more do I need off to hit my target price". The table is hidden when the original price field is empty.
Currency switcher
The dropdown next to the Original Price field switches between 10 currencies (USD, EUR, GBP, CAD, AUD, CHF, TRY, BRL, MXN, INR). The selected currency symbol is applied to all monetary fields and results. Values you have entered are kept when you switch - only the symbol changes.
Share link
Each calculation produces a URL containing the original price, discount, discount type, and currency as hash parameters (for example: #original=80&discount=25&type=percent¤cy=USD). Copy the link and send it - the recipient opens the calculator with your exact values pre-filled. The hash is cleared from the address bar after loading, so the shared values do not linger in browser history.
Saved results
The Save button stores your current calculation. Saved entries appear in a table below the calculator showing date, time, currency, and the four values. Up to 30 results are kept in your browser's local storage; when you reach the limit, the calculator asks before replacing the oldest. Data stays on your device only - it is not synced or sent anywhere.
Frequently Asked Questions
What is a discount?
A discount is a reduction from a product's original price. Discounts can be expressed as a percentage (for example, "25% off") or as a fixed amount (for example, "$10 off"). Stores offer them to clear inventory, attract customers, or reward loyalty. The discount calculator above finds the sale price, savings, or original price when you enter any two of the four values.
What's the difference between percentage discount and fixed discount?
A percentage discount is a portion of the price (for example, "20% off"). The dollar savings depend on the original price: 20% off a $50 item saves $10, but 20% off a $500 item saves $100.
A fixed discount is a set dollar amount (for example, "$20 off"). The savings stay the same regardless of the original price.
How do I calculate 10%, 20%, or 50% off?
The same formula works for any percentage. Multiply the original price by (100 - Discount %) / 100, or equivalently, multiply by the complement: for 10% off multiply by 0.90, for 20% off by 0.80, for 50% off by 0.50.
- 10% off $80 = $80 × 0.90 = $72 (save $8)
- 20% off $80 = $80 × 0.80 = $64 (save $16)
- 50% off $80 = $80 × 0.50 = $40 (save $40)
How do I find the original price from a sale price?
If you know the sale price and the discount percentage, divide the sale price by (1 - Discount % / 100) to find the original price.
Original Price = Sale Price ÷ (1 - Discount % ÷ 100)
A jacket on sale for $90 with 25% off → $90 ÷ (1 - 0.25) = $90 ÷ 0.75 = $120. The original price was $120. In the calculator, enter the sale price and the discount, leave the original price empty, and the result appears.
Why isn't 20% + 10% the same as 30%?
When two discounts are applied one after the other (stacked discounts), they don't simply add up. The second discount applies to the already-reduced price, not the original. A $100 item with "20% off, then extra 10% off" becomes $100 × 0.80 = $80, then $80 × 0.90 = $72 - that is 28% off, not 30%. The combined discount is always slightly less than the sum. For the full formula and a table of common stacks, see the Stacked Discounts section above.
Can a discount be more than 100%?
No. A discount of 100% means the item is free (the buyer pays nothing). A discount above 100% would mean the seller pays the buyer to take the item - this doesn't happen in normal retail. Our calculator accepts discount percentages up to but not including 100%. If you enter 100% or higher, no result is shown, since the math would produce a sale price of zero or below.
Are "discount" and "percent off" the same thing?
Mathematically, "discount" and "percent off" are the same - both reduce the original price by a given percentage. The terms are used interchangeably in retail. We provide two calculators because they cover slightly different scenarios. This Discount Calculator supports both percentage and fixed-amount discounts - useful when you have a coupon for a specific dollar amount. The Percent Off Calculator is simpler and works only with percentages, but includes a quick-pick menu of common percentages (5%, 10%, 15%, ..., 75%) - handy for quick sale-price estimates.
What's the difference between discount and markup?
Discount and markup are opposite operations at different stages of pricing. A discount is a decrease from the selling price - the buyer's perspective. If a $100 item has a 20% discount, the buyer pays $80. A markup is an increase added to the cost - the seller's perspective. If a product costs the seller $80 and they apply a 25% markup, they sell it for $100. Note that 20% discount and 25% markup produce the same two prices ($80 and $100), but they're calculated from different bases. See our Markup Calculator for the seller-side calculation.
Other money-related calculators on Calculator-1.com:
- Markup Calculator - work out the selling price from cost and markup percentage (or any two of cost, markup, selling price, profit).
- Margin Calculator - calculate profit margin from cost and revenue, or solve for any of the related values.
- Percent Off Calculator - find the final price when an item is marked a specific percent off the original.
- Tip Calculator - calculate the tip amount, total bill, and per-person split for any service percentage.
- Money Counter - count physical cash by entering the quantity of each banknote and coin denomination. Supports 10 currencies.
Disclaimer
This calculator and the information above are provided for general guidance only. The formulas and examples shown describe standard retail discount arithmetic; specific offers may include additional rules (minimum purchase, exclusions, expiration) that the calculator does not account for.
The calculator processes your data locally in your browser - original price, discount, sale price, and savings values are not transmitted to our servers. Any saved results stay on your device.
