How to use it
- Enter the original price. Use the full pre-discount amount, e.g. 80. The currency doesn’t matter — just type the number.
- Enter the discount percent. For a “25% off” deal, type 25. Leave it blank (or 0) and the final price simply equals the original.
- Read the results. The Final price card shows what you actually pay; the Amount saved card shows how much the discount knocked off.
Both cards recalculate the instant you change a number, so you can compare deals without pressing a button.
The discount formula
A percentage discount is straightforward once you see the two steps. First find the saving:saved = price × (percent ÷ 100). Then subtract it to get what you pay:final = price − saved. For a 25% discount on a price of 80, that’s 80 × 0.25 = 20 saved and80 − 20 = 60 to pay. You can also get the final price in one move by multiplying by the remaining fraction: price × (1 − percent ÷ 100), which gives 80 × 0.75 = 60 — the same answer.
Common real-world uses
- Sales shopping: check the real price behind a “30% off” or “half price” tag before you buy.
- Comparing deals: see whether 20% off a cheaper item beats 35% off a pricier one.
- Budgeting: confirm a sale item still fits your budget after the discount.
- Selling & pricing: set a promotional price and instantly see the margin you’re giving away.
A quick tip on stacked discounts: taking “20% off, then a further 10% off” is not the same as 30% off. The second discount applies to the already-reduced price, so two cuts of 20% and 10% leave you paying 72% of the original (a 28% total discount), not 70%. To model a stack, run the calculator twice — feed the first result back in as the original price.
Is it private?
Yes. The Discount Calculator is plain JavaScript that runs entirely inside your browser tab. The prices and percentages you type are never uploaded, logged or stored anywhere — there are no accounts and no tracking of your inputs. Once the page has loaded you can even use it offline.
Frequently asked questions
What happens if I enter a discount over 100%?
You can’t save more than the whole price, so anything above 100% is capped at 100% — the final price becomes 0 (free) and the amount saved equals the original price.
Does it handle decimals, like a 7.5% discount or a $19.99 price?
Yes. Both fields accept decimals, and results are rounded to two decimal places for easy reading — perfect for prices and odd percentages.
Can I work out the discount percent from two prices instead?
Not directly here — this tool goes from price + percent to the final amount. To find the percent from an old and new price, divide the saving by the original price and multiply by 100.
Results are rounded for display; for invoices or accounting, double-check critical figures.