Discount Calculator
Work out sale prices and how much you save.
Use on any page (bookmarklet)
Want Discount Calculator without leaving the page you're on? Drag the button below to your bookmarks bar, then click it on any website to open Discount Calculator right there — it runs entirely in your browser.
Use responsibly: a bookmarklet runs on whatever page you click it on. Avoid sensitive sites such as online banking, payment, or healthcare pages — you run it at your own risk. Everything is processed locally and no data is sent anywhere. See our Terms.
- Show your bookmarks bar if it's hidden — Ctrl+Shift+B (⌘+Shift+B on Mac).
- Drag the button above onto the bookmarks bar.
- Open any website and click the bookmark — the Discount Calculator panel appears in the top-right corner. Use ✛ to move it between corners, or ›/‹ to tuck it against the edge and pull it back out.
- Click the bookmark again (or the ✕) to close it.
Note: a few sites with strict security policies may block bookmarklets.
Examples
25% off 80
Input
Price 80, 25% off
Output
You save 20 · Final price 60
15% off 49.99
Input
Price 49.99, 15% off
Output
You save 7.5 · Final price 42.49
Stacked 30% then 20%
Input
100 → 70, then 70 at 20% off
Output
Final 56 = 44% off, not 50%
About this tool
This free online discount calculator works out the sale price and the amount saved as you type. Enter the original price and the discount percentage — the savings and final price update instantly, with no upload and no sign-up.
How to use
- Enter the original price.
- Enter the discount percentage.
- Read your savings and the final price below.
Stacked discounts: the trap worth knowing
The single most common pricing mistake is assuming discounts add up. An item marked 30% off with an extra 20% at the register is not 50% off — the second reduction applies to the already-lowered price. On a 100 item that is 70 after the first cut and 56 after the second, an effective 44%. The shortcut is to multiply what remains rather than adding what comes off: 0.70 × 0.80 = 0.56.
To run stacked offers through this calculator, work in two passes — calculate the first discount, then feed that final price back in as the original price for the second. The order you apply them in makes no difference to the result, though a coupon's terms may still specify one.
Comparing two offers
“10 off” and “20% off” swap places depending on the price. They are worth exactly the same at 50, because 20% of 50 is 10; below that the fixed amount wins, above it the percentage does. Dividing the fixed discount by the percentage as a decimal gives you the crossover price for any pair of competing offers, which is usually faster than testing both.
Going the other way
To check a discount you have already been given, divide the amount saved by the original price. A drop from 80 to 60 saves 20, and 20 ÷ 80 is 25%. Dividing by the sale price instead is the classic error and would overstate it as 33%. The same asymmetry explains why a 50% markup is undone by a 33% discount rather than another 50% — marking up and marking down are not mirror images.
Common uses
Checking a sale price before you reach the till, deciding between two competing coupons, working out clearance margins, converting a wholesale markup into a retail discount, and sanity-checking whether an advertised “up to” percentage applies to the item you actually want. For percentage maths that isn't about prices, the percentage calculator handles increases, decreases, and “X is what percent of Y”, while the VAT calculator adds or removes tax once you have the discounted figure.
Frequently asked questions
How do I calculate a discount by hand?
Multiply the original price by the discount percentage and divide by 100 to get the amount saved, then subtract that from the original price. A faster shortcut for mental maths: subtract the percentage from 100 and multiply. For 25% off 80, that's 75% × 80 = 60, giving you the final price in one step instead of two.
Why doesn't 30% off plus an extra 20% off equal 50% off?
Because the second discount applies to the already-reduced price, not the original. On a 100 item, 30% off leaves 70, and 20% off that 70 is 14 — so you pay 56, an effective discount of 44%, not 50%. Stacked discounts always come out lower than their sum. To find the true rate, multiply the remainders: 0.70 × 0.80 = 0.56, meaning 44% off.
Does the order of two stacked discounts matter?
Mathematically, no — 30% then 20% gives exactly the same result as 20% then 30%, because multiplication is commutative. But the store's terms can still matter: some coupons say they apply to the pre-sale price, and some exclude already-discounted items entirely. The arithmetic is order-independent; the fine print often isn't.
Which is better, a fixed amount off or a percentage off?
It depends on the price, and there's a crossover point. A 10 coupon beats 20% off on anything under 50, and loses above it — because 20% of 50 is exactly 10. Divide the fixed amount by the percentage (as a decimal) to find that threshold for any pair of offers, then check which side of it your item falls on.
How do I work out what discount I actually got?
Divide the amount saved by the original price and multiply by 100. If an item dropped from 80 to 60, you saved 20, and 20 ÷ 80 × 100 = 25% off. Watch the denominator: dividing by the sale price instead of the original is the most common mistake, and it inflates the discount you think you got.
Is the discount applied before or after sales tax?
In almost all systems, percentage discounts are applied to the pre-tax price, and tax is then charged on the reduced amount — so you save on the tax as well. That means the discount percentage you enter here holds true for the tax-inclusive total too. A fixed-amount coupon behaves differently and may be deducted after tax, depending on local rules.
What does "up to 70% off" actually mean?
It means at least one item in the range is 70% off, and says nothing about the rest — the headline number is usually attached to a small number of unpopular sizes or colours. Calculate the real discount on the specific item you want rather than the advertised ceiling.
Does it work with any currency, and with decimals?
Yes to both. The calculator works on plain numbers with no currency attached, so read the results in whatever currency you're shopping in, and prices with decimals are handled with results shown to two places. The calculation runs entirely in your browser.
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