Percent Off Calculator

Stacked discounts and the true final price.

Unit pricing, clearance cycles and loss leaders all shift the effective discount, and store cards promising cash back often carry deferred interest that is charged back to the purchase date if the balance is not cleared in time. Coupon stacking is limited by each retailer's own policy rather than by law.

American list prices are quoted before sales tax, and discounts are frequently stacked — a percentage off, then a coupon on the reduced price — so the order they are applied changes the final number. Retail markdowns are regulated: a "was" price has to be genuine, and margin is the operator's measure rather than the shopper's.

A 50% markup is a 33% margin: the two are measured against different bases, which is the commonest source of confusion in retail arithmetic.

Markup and margin describe the same transaction from opposite ends, and a discount taken off a price that was raised a week earlier is not a saving. Unit price rather than pack price is the fair comparison between two sizes.

Percent Off Calculator sits with the rest of the library's finance work, and it rests on the same retail-pricing arithmetic the way a lender's disclosure or a bank statement does. Its answer is only as good as the assumptions standing behind it.

The quantities it works from — price, first discount and extra discount — are the ones a real retail-pricing question actually turns on, and each carries a convention of its own, set out below.

Money questions in America turn on the same few trade-offs: how long a balance is carried, what rate applies to it, and whether the money is being paid down or built up. Inflation sits behind all of them, since a figure that looks generous at today's prices buys less at tomorrow's, and comparisons across decades are made in real, inflation-adjusted terms.

American products also disclose their costs in prescribed ways, from the APR on a consumer loan to the annual percentage yield on a deposit account.