Discount & Percentage Calculator
Work out a sale price, or solve any everyday percentage.
Discount price
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X% of Y
A is what % of B?
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"25% off" sounds simple until there's a second discount stacked on top, or you're trying to work backward from a sale price to figure out what something cost originally. This page covers the percentage math that trips people up most at checkout.
Why two discounts don't add up the way you'd guess
A "25% off" coupon on top of an already-"20% off" sale price is not 45% off the original price. Each discount applies to whatever the price already is at that point, not to the original price both times. A $100 item at 20% off becomes $80; a further 25% off that $80 is $60 — an effective 40% off the original, not 45%. Discounts stack multiplicatively, not by simply adding the percentages together.
The two percentage questions people actually ask
Most everyday percentage confusion comes down to two genuinely different questions that sound similar: "What is X% of Y?" (a straightforward multiplication — useful for tips, taxes, and discounts) and "A is what percent of B?" (the reverse — useful for figuring out what percentage a discount, raise, or change actually represents). Mixing these two up is the most common source of percentage mistakes; this page has a calculator for each so you don't have to remember which formula goes which direction.
Tips, taxes, and other everyday percentages
The same "X% of Y" math that works out a discount also works out a restaurant tip, a rough sales-tax estimate, or a commission — the operation is identical, only the label changes. An 18% tip on a $64 bill is 0.18 × 64 = $11.52, calculated exactly the same way as "25% off $80." The reverse question — "this $6 tip was left on what size bill, at 20%?" — is the same math as "A is what percent of B," just rearranged. Once the two core operations click, most everyday percentage questions turn out to be one of these two, phrased differently.
Frequently asked questions
How do I calculate a final price after two discounts?
Apply the first discount to the original price, then apply the second discount to that new (already-discounted) price — not to the original again. Run the result back through the "Discount price" calculator above to chain them.
What's the difference between "percent off" and "percent of"?
"Percent off" tells you how much to subtract from a price. "Percent of" tells you the value that percentage represents out of a total — both use the same underlying math, just applied differently. The two mini-calculators above cover each case.
How do I figure out the original price before a discount?
If you know the sale price and the discount percentage, divide the sale price by (1 − discount%) rather than trying to add the percentage back on directly — the same "don't just reverse it by subtracting" logic that applies to removing VAT applies here too.
Can this calculate a tip as well as a discount?
Yes — a tip is just a positive percentage of a total rather than a discount off it. Use the "X% of Y" calculator: enter the tip percentage and the bill total to get the tip amount.
Is this the same math a cash register uses?
Yes — point-of-sale systems apply the same percentage arithmetic behind the scenes. This just lets you check or plan the number in advance, before you're standing at the till.
Can I calculate several items with different discounts at once?
Run each item through the "Discount price" calculator individually, then add up the final prices yourself for your total.