Discount Calculator — sale price, savings & stacked discounts

How it works

Two steps: savings = price × rate, and sale price = price − savings. Equivalently the sale price is price × (1 − rate) in a single step. The part that trips people up is stacking: when a "take an extra 20% off" coupon lands on a sale item already 35% off, the second 20% comes off the reduced $91, not the original $140 — so the effective total is 1 − (0.65 × 0.80) = 48%, not the 55% you'd get by adding. The comparison applies a range of second discounts to your sale price and shows the true combined discount each produces; it is always less than the two rates summed, because every later cut works on a smaller number.

Worked example

The anchor is LibreTexts' published example: a dress discounted 35% off an original price of $140. The amount of discount is $140 × 0.35 = $49, and the sale price is $140 − $49 = $91. Add a second 20%-off coupon and it comes off the $91, not the $140 — landing at $72.80, a 48% effective discount: this calculator's own arithmetic of the stacking.

Frequently asked questions

How do I calculate a sale price?

Multiply the original price by one minus the discount rate: price × (1 − rate). A 35% discount on $140 gives $140 × 0.65 = $91. Equivalently, compute the savings (price × rate = $49) and subtract it — the two routes agree.

Do two discounts add together?

No — they multiply. A 35% discount followed by a 20% discount is 1 − (0.65 × 0.80) = 48% off, not 55%. The second discount is taken off the already-reduced price, so stacked discounts always total less than the sum of their rates. The comparison shows this for several second discounts.

What's the difference between "35% off" and "percent off"?

None — "percent off" is just the discount rate, and this page computes it. Whether a sign says "35% off," "save 35%," or "now 65% of the price," the sale price is the same $91 on a $140 item.

How do I find the original price from a sale price?

Divide the sale price by one minus the discount: sale ÷ (1 − rate). A $91 item that is 35% off was originally $91 ÷ 0.65 = $140. This is the reverse of the sale-price calculation and useful for checking an advertised "was" price.

Is the discount taken before or after tax?

Before — a discount reduces the price, and sales tax is then applied to the reduced amount. So a coupon saves you the tax on the discounted portion too; enter the sale price into the sales-tax calculator to see the final total.

What does the effective discount tell me?

The single discount equivalent to a stack — 48% for a 35%-then-20% combination. It's the honest way to compare a "35% + extra 20%" offer against a flat "45% off": the stack (48%) actually beats the flat 45% here, but not by the 55% the signs might suggest.

How accurate is this, and what does it exclude?

The arithmetic is exact for the price and rate entered. It excludes sales tax (applied after), quantity or bundle deals, minimum-purchase conditions, and rounding a store may apply at the register. For the final amount you pay, run the sale price through the sales-tax calculator.