What a discount calculator does
A discount calculator answers two questions in a second: how much you save and how much you actually pay after a price is marked down. It’s handy for checking whether that “30% off” sticker is worth it, comparing store promotions, or confirming the register charged you the right amount.
Beyond a single discount, this tool chains two markdowns together — a common setup in clearance sales (“30% off, plus an extra 20% at checkout”). That’s where almost everyone slips up: assuming two discounts add together. They don’t, and we prove it with numbers below. Everything runs in your browser; nothing is sent to a server.
How to use the calculator
- Enter the original price of the item.
- Type the discount percentage, or tap one of the quick buttons (10, 15, 20, 25, 30, 50 or 70%).
- Read the result: you’ll see the final price, the amount you save, and the real discount applied.
- If the deal has a second markdown, tick Apply another discount and enter the second percentage.
- With two discounts you’ll get a step-by-step breakdown and the true combined discount.
How a discount is calculated
The final-price formula is simple:
final_price = price × (1 − discount/100)
And the saving is just the difference:
saving = price − final_price
Worked example
A coat costs 1000 and is marked down 25%:
- Final price:
1000 × (1 − 25/100) = 1000 × 0.75 = 750 - Saving:
1000 − 750 = 250
You pay 750 and save 250. Since 25% of 1000 is 250, the numbers check out.
The trap of adding chained discounts
When a store applies 20% and then another 10%, the second discount is taken on the already-reduced price, not the original. That’s why the percentages don’t add up.
Starting from 1000:
- After 20%:
1000 × 0.80 = 800 - After a further 10%:
800 × 0.90 = 720
You saved 280, a real 28%, not the 30% the sum would suggest. Order doesn’t matter: 10% then 20% also lands on 720. Here are some common combinations:
| First discount | Second discount | Naive sum | Real discount |
|---|---|---|---|
| 10% | 10% | 20% | 19% |
| 20% | 10% | 30% | 28% |
| 30% | 20% | 50% | 44% |
| 50% | 20% | 70% | 60% |
The rule of thumb: chaining two discounts always gives a real percentage smaller than the sum.
Frequently asked questions
Is 20% plus 10% the same as 30%?
No. The second discount lands on an already-reduced price, so the real figure is 28%. On a price of 1000 you pay 720 and save 280. To find the true combined rate, multiply the remaining factors: 0.80 × 0.90 = 0.72, meaning you pay 72% and the discount is 28%.
How do I find the discount percentage between two prices?
Subtract the final price from the original, divide by the original, and multiply by 100: (original − final) ÷ original × 100. If an item dropped from 1200 to 900, the discount was (1200 − 900) ÷ 1200 × 100 = 25%.
Discount, markdown, or sale — what’s the difference?
In everyday use they mean the same thing: the price goes down. “Discount” usually means a specific percentage off one item, while “sale” or “markdown” describes a whole campaign or season of reduced prices. The math is identical either way.
Does the result include tax?
No. The calculator works on the price you type in. If that price already includes sales tax, the result does too; if it’s a pre-tax price, you’ll need to add tax separately to know the final amount due.