Discount Calculator
Find the sale price and how much you save from any percent off
๐ท๏ธ Item details
Stacked discount & sales tax (optional)
Applied after the first discount (e.g. an extra coupon).
Added to the discounted price at checkout.
Last updated June 2026
Method: Sale price = original price × (1 − discount ÷ 100); amount saved = original price − sale price. A stacked second discount is applied to the already-reduced price, and any sales tax is applied to the discounted price - exactly how U.S. retailers ring it up.
Included: Sale price, amount saved, effective discount when two discounts stack, a line-by-line price breakdown, and an optional final total with sales tax.
Not included: Retailer-specific rounding rules, item exclusions, minimum-purchase requirements, and rebates or loyalty points. Results are estimates of the checkout total.
Discount calculator: how to find the sale price fast
Say a jacket is priced at $80 and the sign says 25% off. The amount you save is $80 × 0.25 = $20, so the sale price is $80 − $20 = $60. That is the whole job of a discount calculator: turn a "percent off" tag into the real dollars you save and the price you actually pay - and, if you add your local sales tax, the exact number at the register.
The discount formula
The sale price uses one simple formula:
Sale price = Original price × (1 − Discount ÷ 100) And the amount you save is just the difference, which is the same as multiplying by the discount directly:
Amount saved = Original price − Sale price = Original price × (Discount ÷ 100) For the jacket: $80 × (1 − 25 ÷ 100) = $80 × 0.75 = $60 sale price, and $80 × 0.25 = $20 saved. To work backward from a sale price to the original, divide by (1 − discount ÷ 100): a $60 tag at 25% off started at $60 ÷ 0.75 = $80.
Stacked discounts are not additive
This trips up almost everyone. If a store offers 20% off and then an extra 10% off with a coupon, you do not get 30% off. The second discount applies to the already-reduced price, so the math is 0.80 × 0.90 = 0.72 - an effective 28% off. On a $100 item that is $72, not $70. The calculator applies the second discount after the first and shows the true effective rate so you are not surprised.
Where sales tax fits in
In the U.S., sales tax is charged on the discounted price - what you actually pay - not the original sticker price. So the order is: apply the discount(s), then add sales tax to whatever is left. On a $60 sale price with an 8% tax, you pay $60 × 1.08 = $64.80 at checkout. Enter your local rate in the optional section to see the final total. (Manufacturer rebates can be different and may be taxed on the pre-rebate price in some states.)
Percent off vs. dollars off
A $ off coupon is a fixed amount; a % off coupon grows with the price. A flat $20 coupon and 25% off are a tie at exactly $80 - both save $20. Below $80 the dollar coupon wins; above $80 the percentage wins. When you have a choice between two coupons, plug the price into the calculator both ways and compare the amount saved.
How to use this calculator
You only need the price and the discount to get an answer; the rest is optional.
- Enter the original price - the pre-sale sticker or list price of the item.
- Enter the discount as a percentage - the "% off" shown on the tag, sign, or coupon.
- Read the sale price and amount saved - the two numbers update instantly so you can see exactly what you pay and what you keep.
- Add a second discount (optional) - if a coupon stacks on top of the markdown, enter it and the calculator applies it to the already-reduced price and shows the true effective rate.
- Add your sales tax (optional) - enter your local rate to turn the sale price into a real checkout total.
Because every input is optional past the first two, you can use the same tool for a quick "what's 30% off $45?" or a full stacked-coupon, tax-included estimate.
A worked example with two discounts and tax
Suppose a pair of boots lists at $120, the rack says 30% off, and you have a 15% off email coupon that stacks. First discount: $120 × 0.70 = $84. Second discount on the reduced price: $84 × 0.85 = $71.40. That is an effective discount of 1 − (0.70 × 0.85) = 40.5% off, not 45%. Now add 7% sales tax: $71.40 × 1.07 = $76.40 at the register. You saved $120 − $71.40 = $48.60 before tax. Notice that the two discounts together (40.5%) are smaller than simply adding 30 + 15 = 45% - the difference is the 4.5 percentage points you would have overestimated.
Everyday scenarios where this helps
- Clearance racks: confirm that a "final markdown" sign matches the price on the tag before you head to the register.
- Stacking promo codes: check whether an "extra 20% off sale prices" code is worth using versus a single larger coupon.
- Big-ticket purchases: on appliances or furniture, a few percentage points translate into real dollars, so it pays to compute the exact saving.
- Budgeting before you shop: work backward from what you can spend to find the highest original price that still fits after the discount and tax.
- Comparing stores: a deeper percentage at one store can still cost more if its base price is higher - compare final totals, not headline percentages.
Key terms explained
- Original price (list price): the full pre-sale price the discount is taken from.
- Discount rate: the percentage taken off, expressed as "% off."
- Sale price: what you pay after the discount, before tax.
- Amount saved: the dollar difference between the original and sale price.
- Effective discount: the single percentage that matches the combined effect of two stacked discounts.
- Checkout total: the sale price plus any sales tax - the figure you actually pay.
Reverse-engineering a deal
Sometimes you see a sale price and want to check the claim. If a tag says $60 and "25% off," the original should have been $60 ÷ 0.75 = $80. To find the percentage off when you know both prices, use (original − sale) ÷ original × 100; an $80 item now $60 is ($80 − $60) ÷ $80 × 100 = 25% off. Checking the math this way is a quick way to spot inflated "was" prices, where a retailer marks up the list price just so the discount looks larger.
Limitations and assumptions
This calculator assumes the discount applies to the full item price with no exclusions, that any second discount stacks on the reduced price, and that sales tax is charged on the discounted amount - the standard U.S. retail treatment. It does not model minimum-purchase thresholds, brand or category exclusions, manufacturer rebates (which a few states tax on the pre-rebate price), tax-exempt items such as many groceries and clothing in certain states, or retailer-specific rounding. Treat the output as a close estimate of your total, and always read the coupon's fine print for restrictions.
Sources
โ ๏ธ Common mistakes & edge cases
Adding stacked discounts together
20% off plus an extra 10% off is 28% off, not 30%. The second coupon applies to the reduced price. Always multiply the factors (0.80 × 0.90), never add the percentages.
Taxing the original price
Sales tax is charged on the discounted price you actually pay, not the pre-discount sticker. Applying tax before the discount overstates your total.
Confusing "25% off" with "pay 25%"
25% off means you pay 75% of the price. "Pay just 25%" (a 75% discount) is a completely different deal - read the wording carefully before assuming the saving.
Ignoring minimums and exclusions
Many coupons require a minimum spend or exclude sale items and certain brands. The math here assumes the discount actually applies to your item; check the fine print.
❓ Frequently asked questions
How do I calculate a discount?
Multiply the original price by the discount as a decimal to get the amount saved, or by (1 minus the discount) to get the sale price. For example, 25% off a $80 item: $80 x 0.25 = $20 saved, and $80 x 0.75 = $60 sale price.
What is the formula for sale price?
Sale price = original price x (1 - discount / 100). The amount you save is original price - sale price, which is the same as original price x (discount / 100).
How do stacked discounts work?
A second discount applies to the already-reduced price, not the original. So 20% off then an extra 10% off is not 30% off - it is 0.80 x 0.90 = 0.72, an effective 28% off. This calculator applies the second discount after the first and shows the true effective rate.
Do I pay sales tax before or after the discount?
In the United States, sales tax is almost always charged on the discounted price (what you actually pay), not the original price. This calculator applies any sales tax you enter to the sale price to estimate your final checkout total.
What does '25% off' mean in dollars?
It means you pay 75% of the price and save 25%. On a $80 item, 25% off saves you $20 and you pay $60. The higher the original price, the more a given percentage is worth in dollars.
How do I find the original price from a sale price?
Divide the sale price by (1 - discount / 100). For example, a $60 item that was 25% off had an original price of $60 / 0.75 = $80. This reverses the discount formula.
Is a $ off coupon better than a % off coupon?
It depends on the price. A flat $20 off beats 25% off on items under $80, but 25% off wins on items over $80. Compare both: percent off saves more as the price rises, while a fixed dollar amount is constant.
How do I calculate the percentage off if I only know the original and sale prices?
Subtract the sale price from the original, divide by the original, and multiply by 100. For example, an item that dropped from $80 to $60 is ($80 - $60) / $80 x 100 = 25% off. This is useful for verifying that an advertised discount matches the price on the tag.
Does the order of two stacked discounts change the final price?
No. Because the discounts are multiplied, 20% off then 10% off gives the same result as 10% off then 20% off (both are 0.80 x 0.90 = 0.72). The order only matters when one coupon is a fixed dollar amount and the other is a percentage, because a percentage applied first reduces the base the dollar amount comes off of.
How do I figure out the price after a buy-one-get-one (BOGO) deal?
A 'buy one, get one free' deal on two identical items is the same as 50% off each item, so you pay for one and get two. 'Buy one, get one 50% off' works out to 25% off the pair. To use this calculator for BOGO, enter the price of both items as the original and the equivalent percentage as the discount.
Why does my receipt total differ from the calculator by a few cents?
Retailers round at different points - some round each line item, others round only the final total, and tax is rounded to the nearest cent. Item-level rounding can drift a few cents from a single end-of-order calculation. This tool rounds once at the end, so treat the result as a close estimate rather than an exact penny-for-penny receipt.
Can I use this to compare two different sale prices?
Yes. Run each item through the calculator with its own original price and discount, then compare the resulting sale prices and amount saved. The bigger advertised percentage does not always mean the lower final price, so comparing the actual dollar totals is the reliable way to find the better deal.
💡 Good to know
Two discounts never simply add up
"20% off plus an extra 10% off" is an effective 28% off (0.80 × 0.90 = 0.72), not 30%. Multiply the remaining-price factors instead of adding the percentages, and you will never overestimate your saving.
Tax comes after the discount
U.S. sales tax is applied to the discounted price you actually pay, so apply every discount first and add tax to whatever is left. Taxing the original sticker price always overstates your checkout total.
$ off vs. % off flips at the break-even price
A flat dollar coupon and a percentage coupon tie at one price; below it the dollar amount wins, above it the percentage wins. Run both through the calculator and pick the one with the larger amount saved.