Discount calculator, sale price and savings.

A discount calculator gives you the price after a percent or an amount is taken off, and the amount you save. To take a percent off, multiply the price by one minus the percent divided by 100. For 20% off 100, that is 100 × 0.8 = 80, so the sale price is 80 and you save 20. This calculator also stacks a second discount, adds a tax rate that you type, works backwards from a sale price, and compares deals. Each answer shows its steps.

How to use the calculator

1. Pick the job in Work out.
2. For Price after a discount, type the Price before the discount, then the Discount and choose Percent off or Amount off under Taken as.
3. Fill Second discount only if a second one is applied after the first. Leave it empty otherwise.
4. Type a rate into Sales tax rate (optional) to see the tax and the total. Choose whether tax is worked out on the sale price or on the original price.
5. For Original price before a discount, type the sale price and the percent off. For Percent off from two prices, type both prices.
6. For Which deal is better, type the price of one item, the number of items, and set up two or three deals.
7. Copy result copies a sentence with the answer, and Copy link to these numbers shares your inputs.

Two discounts in a row

Percent discounts do not add up. Take 20% off 100 and you pay 80. Take a further 10% off that and you pay 72, because the 10% is taken from 80 and not from 100. The two discounts together are 28 off 100, which is 28% and not 30%. The card Same as one discount of shows this single percent. A third way to see it: 0.8 × 0.9 = 0.72 is what is left of the price.

With a percent and an amount together, the order matters. Start at 100, take 20% off to get 80, then 10 off to get 70. Take the 10 off first and you get 90, then 20% off gives 72. The page shows the other order whenever the two kinds differ.

Adding tax

Type the rate you want to use. The page does not assume one, and it makes no claim about how tax applies to any shop or place. With a sale price of 72 and a rate of 8%, the tax is 72 × 0.08 = 5.76 and the total is 77.76. If you set tax to be worked out on the original price instead, it would be 100 × 0.08 = 8.00, and the total is 80.00.

Finding the original price or the percent off

If a sale price is 60 after 25% off, the 60 is 75% of the original, so the original is 60 ÷ 0.75 = 80. A common slip is to add 25% to 60, which gives 75 and is wrong, because 25% of 80 is more than 25% of 60. To find the percent off from two prices, divide the saving by the original: from 80 to 60 is 20 ÷ 80 = 0.25, which is 25% off. If the second price is higher, the page says it is a rise.

Which deal is better

Deals that look different can be compared by what you pay for the items you want. With items at 20 each and three of them, 25% off costs 60 × 0.75 = 45. Ten off the order costs 60 − 10 = 50. Buy 2 get 1 free costs 2 × 20 = 40, because one of the three is free. The best deal here is the third, and the page marks it.

The best deal can change with the quantity. For one item, 10 off costs 10, 25% off costs 15 and buy 2 get 1 free costs the full 20. The table under the result shows 1 to 8 items, so you can see where the best deal switches. Buy N get M free uses whole numbers, and "every second item" takes the percent off items 2, 4, 6 and so on.

Common mistakes

• Adding the percents of two discounts. 20% and 10% are 28% off together, not 30%.
• Adding the percent back to find the original price. Divide by the share that is left instead.
• Comparing deals on one item only. A deal that wins for one item can lose for five, so check the quantity you really need.
• Forgetting that an amount off may be for the whole order and not for each item. The page treats it as one amount off the order.

To judge the saving, compare the amount saved with the price, not only the percent. 50% off a small item can save less than 10% off a large one.

Rounding

All sums are exact. Prices are rounded to the cent, with halves going up, only where a price is shown. A shop that rounds after every step can differ from this page by a cent. To change a number by a percent without the shopping setting, use the percentage calculator. To see how a discount cuts into your own margin, try the profit margin calculator.