Percent Off Calculator
This percent off calculator takes a list price and a discount and shows the price you pay, the amount you save, and what a second stacked discount or sales tax does to both. It also works backwards from a receipt.
How to use the percent off calculator
There are three modes. Pick the one that matches what you already know.
- Sale price. Enter the original price and the discount percentage. The result updates as you type: the price you pay, the dollars saved, and a bar split into a “you pay” part and a “you save” part.
- Add a second discount. If the sign says something like “extra 15% off sale prices”, put 15 in the second discount field. The calculator applies it to the already-reduced price and reports the combined effective discount.
- Add sales tax. Enter your tax rate and the tax is applied to the discounted price, not the list price. You get the pre-tax subtotal, the tax, and the total at the register.
- Switch to % off when you know the original price and the price paid but not the discount. Enter both and you get the percentage.
- Switch to Original price when you only have the receipt. Enter what you paid and the advertised discount, and it works back to the list price.
The currency selector only changes the symbol in front of the numbers. The arithmetic is identical in dollars, pounds or euros.
The percent off formula
The multiplier is the part worth remembering. A 30% discount has a multiplier of 0.70, because you keep 70% of the price. A 45% discount has a multiplier of 0.55. Once you think in multipliers, every other version of the question becomes a rearrangement of the same equation:
- Amount saved = original − sale price, or equivalently
original × discount ÷ 100. - Discount percentage =
(original − paid) ÷ original × 100. - Original price =
paid ÷ (1 − discount ÷ 100).
Here is what the multiplier does to a $60 item at the discounts stores actually advertise.
| Discount | Multiplier | You pay on $60 | You save |
|---|---|---|---|
| 10% | 0.90 | $54.00 | $6.00 |
| 15% | 0.85 | $51.00 | $9.00 |
| 20% | 0.80 | $48.00 | $12.00 |
| 25% | 0.75 | $45.00 | $15.00 |
| 30% | 0.70 | $42.00 | $18.00 |
| 40% | 0.60 | $36.00 | $24.00 |
| 50% | 0.50 | $30.00 | $30.00 |
| 60% | 0.40 | $24.00 | $36.00 |
| 70% | 0.30 | $18.00 | $42.00 |
| 75% | 0.25 | $15.00 | $45.00 |
Worked examples
Example: 35% off an $84 coat
The multiplier is 1 − 0.35 = 0.65. Multiply the list price by it.
You pay $54.60 and save $29.40. As a check, 29.40 ÷ 84 = 0.35, which is the 35% you started with.
Example: what percent off is $37.50 from $50?
Find the dollars saved first, then express that as a share of the original price.
The discount was 25%. Note the division is by the original price, not by what you paid. Dividing 12.50 by 37.50 gives 33.3%, which answers a different question: how much the sale price would have to rise to get back to list.
Example: working back from a receipt
The receipt says $34.99 and the rack said 30% off. What was the ticket price?
The original was $49.99. Divide, do not multiply. Multiplying $34.99 by 1.30 gives $45.49, and 30% off $45.49 is $31.84, not $34.99.
Why stacked discounts multiply instead of adding
This is the single most common percentage mistake in retail. Two discounts applied one after the other do not add up. The second discount is taken off the already-reduced price, so it is worth less in dollars than it looks.
Follow the money on a $200 jacket. First markdown: 200 × 0.80 = $160. Second markdown: 160 × 0.15 = $24 off, giving $136. Total saved is $64, which is 32% of $200. If the discounts really added to 35%, you would pay $130. The $6 gap is the 15% that was never charged against the first $40 you already saved.
The gap widens as the discounts get bigger. Here is what common pairs actually come to.
| Stacked offer | If you added them | Actual discount | Multipliers |
|---|---|---|---|
| 20% + 10% | 30% | 28% | 0.80 × 0.90 = 0.72 |
| 20% + 15% | 35% | 32% | 0.80 × 0.85 = 0.68 |
| 25% + 20% | 45% | 40% | 0.75 × 0.80 = 0.60 |
| 30% + 20% | 50% | 44% | 0.70 × 0.80 = 0.56 |
| 40% + 25% | 65% | 55% | 0.60 × 0.75 = 0.45 |
| 50% + 20% | 70% | 60% | 0.50 × 0.80 = 0.40 |
| 50% + 30% | 80% | 65% | 0.50 × 0.70 = 0.35 |
| 50% + 50% | 100% | 75% | 0.50 × 0.50 = 0.25 |
The last row is the clearest case: two 50% discounts cannot make something free. Each one halves what is left, so you end up at a quarter of the list price.
Reading the wording on the sign
Store signage usually tells you which behavior you are getting, if you read it closely.
- “Extra 15% off sale prices” or “take an additional 15% off already-reduced items” means stacking. The 15% comes off the ticketed sale price. Use the second discount field.
- “Up to 60% off” is a ceiling, not a promise. Only some items carry the full 60%.
- “30% off, plus 10% off with code” is also stacking, and the order does not matter: 0.70 × 0.90 = 0.63 either way.
- “Now 40% off” on a tag that already shows a reduced price is ambiguous. Check whether 40% has already been taken off the number on the tag or is about to be taken off at the register.
The same logic runs in reverse when you have the final price and want the list price. That is what the reverse percentage calculator is built for.
Where sales tax fits in
A store discount reduces the amount the tax is charged on. The order is: take the discount first, then apply tax to the reduced price. That is how this calculator does it, and it is why the tax figure is smaller on a sale item than on a full-price one.
Example: 30% off an $80 item with 8.25% tax
You pay $60.62. The tax is $4.62, not the $6.60 you would owe on the full $80.
The mistake to avoid is charging tax on the list price and then subtracting a flat dollar discount. Someone doing that gets 80 × 1.0825 = $86.60, minus $24 of discount, which is $62.60. That is $1.98 too high, and the whole gap is tax on money that was never spent.
Multiplication does not care about order, so 80 × 0.70 × 1.0825 and 80 × 1.0825 × 0.70 both come to $60.62. What matters is not the sequence but the base — the discount must be a percentage of the price, and the tax a percentage of the discounted price.
Doing it in your head in the aisle
You rarely need the exact cent while you are standing in a store. These shortcuts get you close enough to decide.
- 10% is a decimal shift. 10% of $47.90 is $4.79. Every other round percentage is built from it: 20% is double, 5% is half, 30% is triple.
- 25% off is a quarter off. Divide by 4 and subtract. 25% off $36 is 36 − 9 = $27.
- 33% off is roughly a third off. $45 becomes about $30.
- Flip the problem. For 70% off, it is faster to find 30% of the price than to find 70% and subtract. 30% of $80 is $24, so that is what you pay.
- 15% is 10% plus half of 10%. On $62: $6.20 + $3.10 = $9.30 off.
Once you have the shelf price, per-unit cost is the number that actually decides between two brands. The unit price calculator handles that comparison, including cases where a discounted big box is still worse value than a full-price small one.
If you are on the other side of the counter and setting the ticket price rather than reading it, the markup calculator works out what a discount does to your margin.
Common mistakes
- Adding stacked discounts. 20% then 15% is 32%, not 35%. Multiply the multipliers.
- Dividing by the sale price instead of the original. To find the discount percentage, divide the savings by the price before the discount. $12.50 saved on a $50 item is 25% off, not 33%.
- Multiplying to reverse a discount. If you paid $120 after 20% off, the original is 120 ÷ 0.80 = $150, not 120 × 1.20 = $144.
- Taxing the list price. Tax goes on the discounted amount, so the tax you pay drops with the discount.
- Confusing “50% off” with “50% of”. They land on the same number for 50% only. “40% of $90” is $36; “40% off $90” is $54.
- Rounding at every step. Round once, at the end. Rounding the sale price before the second discount can throw the total off by several cents.
- Treating “up to 70% off” as the discount on your item. Check the individual tag.
Frequently asked questions
What is 20% off $50?
It is $40. The multiplier for 20% off is 1 − 0.20 = 0.80, so 50 × 0.80 = 40. You save $10. As a check, 10 ÷ 50 = 0.20, which is the 20% you started with. If sales tax applies, it is charged on the $40, not on the original $50.
What is 15% off $75?
It is $63.75, and you save $11.25. The quickest route is 75 × 0.85 = 63.75. In your head: 10% of $75 is $7.50, half of that is $3.75, and $7.50 + $3.75 = $11.25 off. Subtract that from $75 to get the sale price.
Is 20% off then 15% off the same as 35% off?
No. It works out to 32% off. The two multipliers multiply: 0.80 × 0.85 = 0.68, so you keep 68% of the price and save 32%. On a $200 item you pay $136, not the $130 that a flat 35% would give. The second discount only applies to what is left after the first one.
What does “extra 30% off sale prices” mean?
It means the 30% comes off the ticketed sale price, not the original price. If an item was $90 and is marked down to $63, an extra 30% takes it to 63 × 0.70 = $44.10. Relative to the original $90 that is 51% off, because 0.70 × 0.70 = 0.49.
How do I find the original price from what I paid?
Divide by the multiplier. If you paid $60 after 25% off, the multiplier was 0.75, so the original was 60 ÷ 0.75 = $80. Use the Original price mode. The mistake is to add the percentage back on: 60 × 1.25 = $75, and 25% off $75 is $56.25, which is not what you paid.
What percent off did I get if an $80 item cost me $52?
35% off. Take the savings first: 80 − 52 = 28. Then divide by the original price: 28 ÷ 80 = 0.35, which is 35%. Always divide by the price before the discount. Dividing by the $52 you paid gives 53.8%, which answers how much the sale price would have to rise to reach list.
Is sales tax calculated before or after the discount?
After. The discount reduces the taxable amount, then tax is applied to the reduced price. On a $80 item at 30% off with 8.25% tax: 80 × 0.70 = $56, tax is $4.62, total $60.62. Charging tax on the full $80 first and then subtracting the dollar discount would overcharge you by $1.98.
Can two 50% discounts make something free?
No. Each one halves what remains, so together they leave you paying a quarter of the list price: 0.50 × 0.50 = 0.25, or 75% off. A $120 item becomes $60, then $30. The only way a stack of percentage discounts reaches zero is if one of them is 100%.
How do I calculate a discount without a calculator?
Start with 10%, which is just moving the decimal point one place left. On $46.80 that is $4.68. Build the rest from it: 20% is double, 5% is half, 15% is 10% plus 5%. For discounts above 50%, work out what you keep instead. For 70% off, find 30% of the price and that is the answer.
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