🏷️ Discount Calculator

Find the sale price and how much you save on a discount, then optionally add sales tax on top of the discounted price.

Original price

Discount (%)

Sales tax after discount (%, optional)

Three lines of arithmetic

saved      = price x (discount / 100)
sale price = price - saved
total      = sale price x (1 + tax / 100)

With the defaults, 25% of $120 is $30, so the sale price is $90. Add an 8% sales tax and you hand over $97.20. Note the order: tax is applied to the discounted $90, not the original $120, which is how US registers actually ring it up. A store coupon lowers your tax bill along with the price; a manufacturer rebate mailed to you afterwards does not.

Stacked discounts do not add up

"30% off, then an extra 20% off at the till" is not 50% off. The second cut applies to the already-reduced price, so you multiply what is left:

$120 - 30% = $84, then $84 - 20% = $67.20.
That is 0.70 x 0.80 = 0.56 of the original, so 44% off, not 50%.
To chain them here, enter 44 as the discount, or run the tool twice using the first sale price as the second original price.

To work backwards from a sale price, divide rather than add the percentage back. A $67.20 tag at 44% off came from $67.20 / 0.56 = $120. Adding 44% to $67.20 gives $96.77, which is wrong.

Frequently asked questions

What is 25 percent off $120?

$90. A quarter of $120 is $30, so you save $30 and pay $90 - or $97.20 once 8% sales tax is added to the discounted price.

Is sales tax charged before or after the discount?

After, on the amount you actually pay. That is what this calculator does. The exception is a manufacturer rebate, which is not a price cut at the register, so tax is charged on the full ticket price.

How do I work out the original price from a sale price?

Divide by one minus the discount as a decimal. A shirt marked $67.20 after 44% off started at $67.20 / 0.56, which is $120.