Discount Calculator

How it works

Discount calculation finds the sale price after applying a percentage off. Sale price = original × (1 − discount/100). The amount saved is original × discount/100. This calculator also adds sales tax to the discounted price — important because in most US states, sales tax is calculated on the discounted price, not the original.

For "stacked" discounts (e.g., "20% off, then an extra 10% off"), the discounts compound: a $100 item with 20% off is $80, then another 10% off is $72 — equivalent to a 28% total discount, not 30%. Always apply percentages sequentially when stacking; don't add them together.

For comparison shopping, check the unit price (price per ounce, per item) rather than the absolute price. A $4 box with 50% off can still be more expensive per unit than a $5 box at full price if the smaller box has fewer units. Most stores show unit pricing on shelf tags.

Buy-X-get-Y-free deals: a "buy 1 get 1 free" is effectively a 50% discount when you buy 2; "buy 2 get 1 free" is 33%, "buy 3 get 1 free" is 25%. Don't be fooled — work out the actual percentage if you weren't going to buy multiples anyway.

Common pricing tactics that aren't great deals. "Was $200, now $99" — check if $99 is the typical price (the inflated "was" price is just decorative). "Save 50%" on something you don't need is 100% wasted money. "Free shipping over $X" — look at the actual delivered cost vs. competing options.

Sales tax. The discounted price is the taxable amount in most US states. Sales tax rates range from 0% (Oregon, Delaware, New Hampshire, Alaska, Montana) to 9-10% in some California cities. Online purchases generally now collect sales tax based on your shipping address (post-2018 South Dakota v. Wayfair).