Discount calculator — including the one where 20% and 10% make 28%
Work out what you pay and what you save, stack two or three discounts and see the real total, or run it backwards from the sale price to the original. Every answer prints the arithmetic that produced it, so you can check it against the tag on the shelf. Nothing is uploaded or saved.
- Nothing is uploaded or saved
- Works offline
The everyday one. Enter the price on the tag and the percentage on the sign, and see what you hand over and what you keep.
25% off RM 120.00
RM 90.00
You save RM 30.00
25% off RM 120.00
= RM 120.00 × 0.75
= RM 90.00
Saving = RM 120.00 − RM 90.00 = RM 30.00
Splitting a restaurant bill instead of a shop price? The tip calculator handles the service charge and hands out the odd cents so the shares add up.
For percentage questions with no price in them — a percentage change, a share of a total — the percentage calculator is the shorter road.
How it works
- 1
Pick the question you actually have
Four of them fit on this page. A price and a percentage off is the everyday one. Stacked discounts is for a sign that promises a further reduction at the till. Working backwards starts from what you were charged. And “how much off is this?” takes two prices and gives you the percentage between them — the one you want when a sign shows both figures and no percentage at all.
- 2
Type the price as it is printed
The field takes “1,299.90” straight out of a spreadsheet or off a receipt; commas and spaces are ignored. It is a text field rather than a number one on purpose, so the arrow keys cannot nudge a price while you are scrolling the page on a phone in a shop.
- 3
Stack discounts in the order the till applies them
Add a line for each one. The table on the right shows what each discount is actually worth in money, which is usually the surprise: on a 120 item, 20% takes off 24.00 and the further 10% takes off only 9.60, because it comes off 96.00 and not off 120.00. The order does not change the final price — multiplying is multiplying — but it does change which line looks generous.
- 4
Add a tax rate only if you know it
The tax field starts empty and stays empty until you fill it in. There is no rate built in, because the right one depends on what you are buying and where. Then say what the price you typed already contains: a price that excludes tax has tax added on top of the discounted figure, while a shelf price that already includes it does not — and those two readings of the same typed number give different totals.
- 5
Read the working, not just the number
Under every answer is the line that produced it — the multiplier, the subtraction, the division. That is what makes the page checkable with the calculator on your phone, and it is what tells you whether the figure you were quoted at the counter was right. Copy the working to the clipboard if you want to send it to whoever is arguing with you about it.
Frequently asked questions
Is 20% off and then a further 10% off the same as 30% off?
No, and this is the single most useful thing on this page. Take 100. The first discount leaves 80. The second is 10% of 80, not of 100, so it takes off 8 rather than 10 and leaves 72. You paid 72, so the saving is 28 — a 28% discount, not a 30% one. The gap widens as the discounts get bigger: 50% and then a further 50% leaves 25, which is 75% off and not 100% off, because the second half is a half of what is left rather than a half of the original. Stacked percentages multiply, they do not add.
Does the order of two stacked discounts matter?
Not to the total. Multiplying by 0.8 and then by 0.9 gives 0.72, and multiplying by 0.9 and then by 0.8 gives 0.72 as well — the same 28% off either way. What changes is what each individual line is worth. On a 100 item, applying the 20% first takes off 20.00 and then 8.00; applying the 10% first takes off 10.00 and then 18.00. If one of the discounts is a voucher with a maximum value, or the till prints them as separate savings, that difference is worth watching even though the price at the end is identical.
Why does adding 25% back to a discounted price not give me the original?
Because the two percentages are shares of different numbers. If 160 is reduced by 25% you pay 120. Adding 25% to 120 gives 150, not 160 — the discount was 25% of 160, which is 40, while the increase is 25% of 120, which is only 30. To undo a discount you divide instead of multiplying: 120 ÷ 0.75 = 160. That is what the “work backwards” mode on this page does, and it is the mode you want when you have a receipt and need the pre-sale price for a claim or a return.
Should tax be worked out before or after the discount?
The order genuinely does not matter, and most pages that fuss about it are chasing the wrong question — multiplying by 0.8 and then by 1.06 gives exactly the same figure as multiplying by 1.06 and then by 0.8. What does matter is whether the price you typed already carries the tax. Take 100 with a 20% discount and a 6% tax rate. If the 100 excludes tax, you pay 80 and then 4.80 of tax on top, so 84.80 leaves your account. If the 100 already includes tax, you pay 80 in total, and the tax hidden inside that 80 is 80 × 6 ÷ 106 = 4.53, leaving 75.47 as the price of the goods. Same typed number, two different totals — which is why this page asks.
Why is there no tax rate filled in for me?
Because there is no single right one to fill in. Rates differ by category, by country, and over time, and a shopping page is used from everywhere. A default rate sitting in the box would look authoritative and be wrong for most of the people who read it — the same reason this site does not bundle a list of public holidays into its date calculator. Take the rate off your own receipt or invoice, type it in, and the page will show you exactly what it did with it.
Is “buy one get one free” the same as 50% off?
On two identical items, yes. Two 60 items where the second is free means you hand over 60 for 120 worth of goods, which is 50% off the pair. But “buy one get one half price” is not 25% off each item — it is 60 + 30 = 90 for 120 worth, which is 25% off the pair and nothing at all off the first item. The catch in both is the same: the discount only exists if you wanted two. Put the pair price in the “how much off is this?” mode above — before 120, now 90 — and the page will tell you it is 25%.
My receipt is a cent away from what this page says. Which is wrong?
Probably neither. Every figure here is worked out in whole cents and only one number in each answer is rounded — the amount you pay — with the saving derived from it by subtraction, so the two always add back to the original price. A till may round differently: some round the discount rather than the price, some apply the discount per line item and then total, some round the whole basket at the end. On a single item the difference is at most a cent; across a long receipt it can be a few. If the gap is larger than that, the discount that was applied is not the one on the sign.
Can I use this for a clearance price that keeps dropping?
Yes, and stacked mode is the honest way to do it. A rail marked “40% off, then a further 20% off marked-down stock” is two discounts, not a 60% one: 100 becomes 60 and then 48, which is 52% off. Enter them as two lines in the order the sign describes and the table shows what each stage actually removed. If you only have the two prices and no percentages at all, use “how much off is this?” instead — it needs nothing but the old figure and the new one.
Does anything I type here leave my browser?
No. The arithmetic runs in the JavaScript this page has already loaded, there is no upload of any kind, and nothing is written to localStorage — so closing the tab leaves nothing behind and the page keeps working with the network off. That matters more than it sounds for a shopping tool: the prices people check here are quotes, staff discounts and things they have not decided to buy yet.