🏷️ Discount Calculator: Percent Off and Sale Price
By ToolNimba Editorial Team · Updated 2026-06-20
This discount calculator turns a percent-off sale into real numbers. Enter the original price and the discount percentage, and you will instantly see the final price you pay and the amount you save. There is also an optional second discount field, so you can model stacked offers like an extra coupon on top of a sale and see what the deal truly comes to.
What is the Discount Calculator?
A discount is a reduction in price, almost always expressed as a percentage of the original price. The maths is short: the amount you save is the original price multiplied by the discount percent divided by 100, and the price you pay is whatever is left. So a 25% discount on a $100 item saves you $25 and leaves you paying $75. The percentage is the only lever, which is why a quick calculation can tell you in seconds whether a "huge" sale is actually a good deal.
There are two main kinds of discount, and they behave differently. A percentage discount (such as 30% off) scales with the price, so it is worth more in dollars on expensive items. A fixed-amount discount (such as $20 off) is worth the same no matter the price, so it is proportionally a bigger deal on cheaper items. A $20 coupon is a 40% saving on a $50 item but only a 4% saving on a $500 item, while a flat 10% off is always 10% whatever the price. When a store offers you a choice between the two, this tool lets you compare the real cash you keep instead of guessing.
The more interesting case is stacked or double discounts, where two offers apply to the same item, for example a 20% off sale plus an extra 10% coupon at checkout. A common mistake is to add the percentages and assume 30% off. Discounts almost always apply one after another, so the second one comes off the already-reduced price, not the original. Twenty percent off $100 is $80, and 10% off $80 is $72, which is a 28% effective discount rather than 30%. The order does not change the final price (multiplication is commutative), but stacking always saves you a little less than the two rates added together.
Knowing the effective discount helps you compare offers fairly. A single "30% off" beats "20% off plus 10% off", and "buy one get one half price" is really a 25% discount across the two items, not 50%. The calculator above does the arithmetic for you and, when you stack two discounts, spells out the true combined percentage so you are never fooled by clever signage.
Discounts also work in reverse. If you only know the sale price and the percent off, you can recover the original price by dividing the sale price by one minus the discount as a decimal. An item that costs $75 after 25% off was originally $75 divided by 0.75, or $100. This reverse calculation is handy for checking that a "was" price on a tag is genuine, for working out a list price from a quoted net figure, or for pricing your own products to land on a clean number after a planned markdown.
Finally, remember that the discount is only one part of the receipt. The percent off applies to the listed price, but sales tax, shipping, and any service or handling fees are usually added to the discounted price afterward. A 30% off deal can still cost more at the till than a competitor advertising a smaller discount if one charges tax or delivery and the other does not, so always compare the final out-the-door total rather than the headline percentage.
When to use it
- Checking the final sale price of a clothing or electronics item before you reach the till.
- Working out whether a stacked coupon plus sale beats a single bigger discount elsewhere.
- Deciding between a percent-off deal and a fixed dollar-off coupon on the same purchase.
- Recovering the original price from a sale tag to confirm a "was" price is genuine.
- Setting a markdown as a shop owner and confirming the price customers will actually pay.
- Adding sales tax to a discounted price to see the true out-the-door total.
How to use the Discount Calculator
- Enter the original price of the item.
- Enter the discount percentage, or tap one of the quick buttons.
- If two offers apply, enter the second discount percent in the optional field.
- Read off the price you pay and the amount you save, plus the true combined discount when stacking.
Formula & method
Worked examples
A $100 jacket marked 25% off.
- saved = 100 × 25 ÷ 100 = $25.00
- final = 100 − 25 = $75.00
Result: You pay $75.00 and save $25.00
An $80 pair of shoes at 20% off with an extra 10% coupon stacked on top.
- after first = 80 × (1 − 20 ÷ 100) = $64.00
- final = 64 × (1 − 10 ÷ 100) = $57.60
- saved = 80 − 57.60 = $22.40
- effective discount = 22.40 ÷ 80 × 100 = 28% (not 30%)
Result: You pay $57.60 and save $22.40, a 28% effective discount
Reverse: a gadget costs $75 after a 25% off sale. What was the original price?
- discount as a decimal = 25 ÷ 100 = 0.25
- remaining fraction = 1 − 0.25 = 0.75
- original = 75 ÷ 0.75 = $100.00
Result: The original price was $100.00
Percent off vs fixed amount: a $40 item with either 25% off or a $12 coupon.
- percent route: 40 × 25 ÷ 100 = $10.00 saved, pay $30.00
- fixed route: $12.00 saved, pay $28.00
- the $12 coupon saves $2.00 more on this lower-priced item
Result: The $12 fixed coupon wins here, paying $28.00 vs $30.00
Sale price and saving for common discounts on a $100 item
| Discount | You save | You pay |
|---|---|---|
| 10% off | $10.00 | $90.00 |
| 15% off | $15.00 | $85.00 |
| 20% off | $20.00 | $80.00 |
| 25% off | $25.00 | $75.00 |
| 33% off | $33.00 | $67.00 |
| 40% off | $40.00 | $60.00 |
| 50% off | $50.00 | $50.00 |
| 70% off | $70.00 | $30.00 |
| 75% off | $75.00 | $25.00 |
True combined discount when stacking two offers
| First discount | Second discount | Effective discount |
|---|---|---|
| 10% | 10% | 19% |
| 20% | 10% | 28% |
| 25% | 15% | 36.25% |
| 30% | 20% | 44% |
| 40% | 30% | 58% |
| 50% | 20% | 60% |
Percent off vs a $20 fixed coupon at different prices
| Original price | 20% off saves | $20 coupon saves | Better deal |
|---|---|---|---|
| $50 | $10.00 | $20.00 | $20 coupon |
| $80 | $16.00 | $20.00 | $20 coupon |
| $100 | $20.00 | $20.00 | Tie |
| $150 | $30.00 | $20.00 | 20% off |
| $300 | $60.00 | $20.00 | 20% off |
Common mistakes to avoid
- Adding stacked percentages together. A 20% sale plus a 10% coupon is not 30% off. The coupon comes off the already-reduced price, giving an effective 28%. Always multiply the remaining fractions rather than summing the rates.
- Confusing percent off with the price you pay. 40% off does not mean you pay 40% of the price. You pay the remaining 60%. The discount percent is what you save, not what you spend.
- Reversing a discount by adding the percent back. If an item is $75 after 25% off, the original is not 75 plus 25% (which gives $93.75). The 25% came off the larger original, so you divide: 75 ÷ 0.75 = $100. Always divide by one minus the rate.
- Assuming percent off always beats a fixed coupon. A flat dollar-off coupon can be the better deal on cheaper items. A $20 coupon beats 20% off on anything under $100, and only loses on more expensive purchases. Compare the actual dollars saved.
- Ignoring tax and fees. The discount applies to the listed price, but sales tax, shipping, or service fees are usually added afterward. The final amount on your receipt can be higher than the discounted price shown here.
- Trusting an inflated "was" price. A big percent off a marked-up original is not a real saving. Use the reverse calculation or compare the final price to other stores to check the deal is genuine rather than just well advertised.
Glossary
- Discount
- A reduction from the original price, normally stated as a percentage of that price.
- Original price
- The full price before any discount is applied. Also called the list price or sticker price.
- Sale price
- The price you actually pay after the discount, equal to the original price minus the amount saved.
- Percent off
- The discount expressed as a percentage of the original price, so 30% off means you keep 70% of the price.
- Fixed-amount discount
- A flat cash reduction such as $20 off, worth the same in dollars regardless of the item price.
- Stacked discount
- Two or more discounts applied to the same item in sequence, where each one reduces the running price further.
- Effective discount
- The single percentage that equals the total saving from stacked discounts, always less than the rates added together.
- Reverse discount
- Working backward from a sale price and percent off to recover the original price, by dividing by one minus the rate.
Frequently asked questions
How do I calculate a discount?
Multiply the original price by the discount percent and divide by 100 to get the amount saved, then subtract that from the price. For example, 25% off $80 saves $20, so you pay $60.
How do I work out the sale price?
Multiply the original price by (1 minus the discount as a decimal). A 30% discount means you pay 70% of the price, so a $50 item costs $50 × 0.70 = $35.
Is 20% off plus 10% off the same as 30% off?
No. Stacked discounts apply one after another, so the 10% comes off the already-reduced price. On $100 that is $72, an effective 28% off, slightly less than a straight 30%.
How do I find the original price from a sale price?
Divide the sale price by (1 minus the discount as a decimal). If an item cost $75 after 25% off, the original was $75 ÷ 0.75 = $100. Do not just add the percent back, that gives the wrong answer.
How do I calculate percent off a price?
Percent off is the discount rate applied to the original price. Divide the percent by 100, multiply by the price, and that is what you save. The rest is what you pay.
Does the order of two discounts change the final price?
No. Applying 20% then 10% gives the same result as 10% then 20%, because multiplication is commutative. The final price and total saving are identical either way.
Which is better, a percentage discount or a fixed amount off?
It depends on the price. A fixed coupon like $20 off is the bigger saving on cheaper items, while a percentage like 20% off wins on more expensive ones. A $20 coupon and 20% off tie at exactly $100.
How do I find what percentage discount I got?
Divide the amount you saved by the original price and multiply by 100. If a $120 item cost $90, you saved $30, and 30 ÷ 120 × 100 = 25% off.
Is the discount calculated before or after tax?
Discounts are normally applied to the pre-tax listed price, then sales tax is added to the reduced amount. So you pay tax on the lower sale price, not the original, but the final receipt is still higher than the discount shown here.
What does "buy one get one 50% off" really save me?
It is a 25% discount across the two items, not 50%. You pay full price for one and half for the other, so two $40 items cost $60 instead of $80, which is 25% off the pair.