Discount Calculator
Calculate sale price, savings and reverse discounts from a percentage or fixed amount off.
🔒 Runs entirely in your browser — nothing is uploadedDiscount formula
A percentage discount reduces an original price by a fraction of that price. The formula is final price = original price × (1 − discount percentage ÷ 100). For example, 25% off a 120 item is 120 × 0.75, giving a final price of 90 and savings of 30. A fixed amount discount is even simpler: final price = original price − amount off. The calculator also reports the effective percentage so a coupon for 15 off can be compared with a store sign that says 10% off.
Reverse discount mode is useful when you know the final sale price and the percent off but want to recover the original tag price. It rearranges the same formula: original price = final price ÷ (1 − discount percentage ÷ 100). The widget validates impossible 100% reverse discounts because dividing by zero would not produce a meaningful original price.
When to use each mode
Use percent mode for sale signs, seasonal promotions and markdowns such as 20% off. Use amount mode for coupons, rebates or credits that subtract a fixed value from the ticket price. Use reverse mode when a receipt, ad or marketplace listing gives a sale price and discount percent but hides the original. Because results update instantly, you can compare several coupons and decide which offer produces the lower final price before taxes or shipping.
Practical checkout notes
Real stores may round per item, apply coupons before or after other promotions, exclude some items, or calculate tax after the discounted subtotal. This page focuses on the discount math only and does not call a retailer, payment service or currency API. Treat the result as a clear estimate, then check the final cart or receipt for local tax, shipping, fees and policy details.
Worked examples and stacked discounts
A 35% markdown on an 80 item leaves 80 × 0.65 = 52, a saving of 28. A fixed coupon of 15 off a 60 item leaves 45, which is an effective 25% discount. In reverse mode, a sale price of 68 after 15% off means the original price was 68 ÷ 0.85 = 80.
Discounts do not simply add up when they are applied one after another. Taking 20% off and then a further 10% multiplies the factors: 0.80 × 0.90 = 0.72, so you pay 72% of the original price, a total discount of 28% rather than 30%. To model this here, run the first discount, then enter its final price as the original price for the second. In reverse mode, always confirm which price the percentage was based on, since a percentage off a sale price is not the same as a percentage off the original.
How to use
- Choose a modeCalculate a percent discount, a fixed amount off, or reverse a sale price back to the original price.
- Enter price detailsType the known price and discount value. Labels change to match the selected mode.
- Read savingsUse the final price, amount saved and effective discount rate for checkout or comparison.