Math
Discount Calculator
Calculate the real price of a deal, including stacked coupons, tax, reverse original price, and percent-off comparisons.
Try an example
Result
Sale price
—
- You save
- —
- Effective discount
- —
- After-tax total
- —
Student quick launch
Grade planning, algebra checks, and formulas students reach for most.
Study path
Use this calculator with
Follow these when you want the formula behind the answer, a short lesson, or nearby tools in the same topic.
What this discount calculator can solve
| Mode | Use it when | Output |
|---|---|---|
| Sale price | You know original price and percent off | Sale price, savings, effective discount, and tax |
| Stack discounts | You have a sale plus a coupon | Compounded final price and true effective discount |
| Find original | You know sale price and percent off | Original list price and dollars saved |
| Find % off | You know original and sale prices | Discount percent and savings |
How sale price is calculated
The savings are the original price minus the sale price. If you enter tax, the calculator applies tax after the discount.
How stacked discounts work
Stacked discounts compound instead of adding. A 20% discount followed by a 10% coupon leaves 72% of the original price, so the effective discount is 28%, not 30%.
Worked examples
$99.99 at 25% off
Find sale price and savings
Sale price
$74.99
30% off plus 15% coupon
Stacked discount example
Sale price
$71.40
$60 after 40% off
Recover original price
Sale price
$60.00
$80 down to $64
Find percent off
Sale price
$64.00
Frequently asked questions
Do stacked discounts add together?+
No. They compound. A 20% discount followed by another 20% discount is 36% off, not 40% off.
Is sales tax calculated before or after a discount?+
Usually after the discount in the United States, although rules can vary for coupons and rebates. This calculator applies tax to the discounted subtotal.
How do I find the original price from a sale price?+
Divide the sale price by 1 minus the discount rate. For example, $60 after 40% off means $60 / 0.60 = $100 original.
What if the sale price is higher than the original price?+
Then the result is a markup instead of a discount. The calculator warns you in Find % off mode.
About this calculator
- Written by
- mathcheck editorial team
- Last reviewed
- May 8, 2026
Method
- Uses the values entered by the user and stable formulas documented on the page.
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Last updated: May 8, 2026