Discount Calculator

What Does “40% Off” Actually Cost?

Sales are designed to make percentages feel bigger than the math says. “40% off”, “extra 20% at checkout”, “was 129.99, now…” — every formulation nudges you toward feeling the discount rather than computing it. This calculator computes it: enter the original price and the discount, and read the final price and the exact money saved. It also handles the cases stores hope you will not check — stacked discounts, reverse calculations, and tax added after the discount — instantly and in your browser.

The Calculations It Covers

1. Simple discount: original price and percent off → final price and savings. The everyday case, solved as you type.
2. Stacked discounts: “30% off, plus an extra 20% with code.” This is not 50% off — the second discount applies to the already-reduced price, so the true total is 44%. The calculator chains them correctly and reports the real combined percentage.
3. Reverse discount: you know the final price and the discount — what was the original? Useful for checking whether a “was” price is honest, and for pricing your own goods backward from a target sale price.
4. Tax after discount: add a tax percentage and see the at-the-register total, computed in the order stores actually apply it (discount first, then tax).

The Stacking Trap, Once and For All

Sequential percentages multiply, never add. Two 25% discounts leave you paying 75% × 75% ≈ 56% — a 44% total discount, not 50%. The gap grows with bigger numbers: 50% plus “an extra 50%” is 75% off, not free. Retail copywriters know shoppers add instinctively; now your calculator knows they multiply. The combined-percentage readout makes the honest figure visible at a glance, which is occasionally the difference between a genuine bargain and good marketing.

Shopping Math Worth Internalizing

• Compare savings in money, not percent. 40% off something cheap can save less than 10% off something expensive — the savings field exists precisely for this comparison.
• Check “was” prices in reverse. If the claimed original is implausible for the product, the discount is theater. The reverse mode reconstructs originals in one step.
• Unit thinking beats sticker thinking: for consumables, the discounted price per unit (per kilogram, per wash) is the comparable number across brands and pack sizes.
• A discount on something you would not otherwise buy saves −100%. No calculator can fix that one; it can only make the real numbers impossible to ignore.

Fast, Private, Always in Your Pocket

The page is built for the moment of decision: in a shop aisle, at a checkout screen, mid-negotiation. Results update live with every keystroke, the arithmetic is exact, and nothing you type is transmitted anywhere — the calculation runs locally and the page keeps working offline once loaded. Pair it with the Percentage Calculator for the general cases beyond shopping, and the Tip Calculator's cousin questions are covered by the same family of tools on this site.

During major sale seasons, one habit repays itself many times over: before the sale begins, note the real prices of the items you actually want. When the banners arrive, the reverse mode tells you whether "70 percent off" is measured against a genuine price or an inflated reference — and the stacked mode tells you what the coupon code on top really adds. Sales reward prepared shoppers and exploit unprepared ones; this page is the preparation.