A 20.00% coupon on a 140.00 cart saves 28.00, for a final total of 112.00.
Coupons come in two shapes, a percentage off, or a fixed dollar amount off, and they don't compare directly at face value. A $15 coupon and a 15% coupon deliver very different actual savings depending on the size of the cart they're applied to.
Retailers choose between the two formats deliberately: a fixed-dollar coupon caps their exposure on large orders, while a percentage coupon scales with cart size, so which one benefits the shopper more depends entirely on how much is in the cart.
As a rule of thumb, a fixed-dollar coupon tends to win on smaller carts and a percentage coupon tends to win on larger ones, but the exact crossover point depends on both coupon values, so it's worth checking rather than assuming.
A fixed-dollar coupon's effective percentage is exactly a percentage decrease calculation, the coupon amount is the "amount decreased," the cart total is the "original value," and dividing one by the other gives the same rate a percentage coupon would need to advertise to match it. That effective rate changes with every cart total, which is the genuine insight a fixed coupon's face value alone doesn't show.
Shoppers presented with multiple coupon options at checkout can pick the one that actually saves more on their specific cart.
Retailers test fixed versus percentage coupon offers in marketing campaigns, since the two perform differently depending on typical order size.
Reward point redemptions are often issued as fixed-dollar credits, whose effective value as a percentage discount depends entirely on how much a member spends.
Questions specific to comparing coupon formats, which is where most of the confusion between percentage and fixed-dollar savings comes from, especially at checkout when only seconds are available to decide.