In economics, the benefit buyers receive when they pay less than they were willing to pay is called consumer surplus.
A buyer’s willingness to pay is the maximum amount that buyer would accept paying for a product. If the market price is lower, the difference between willingness to pay and the actual price is that buyer’s surplus. Adding these differences across buyers gives total consumer surplus, usually represented as the area below the demand curve and above the market price.
For example, if someone would pay $20 for a book but buys it for $14, that purchase creates $6 of consumer surplus. The calculation describes economic benefit rather than cash handed back to the buyer. It also depends on assumptions about preferences, comparable choices, and a well-defined market.
Consumer surplus is often discussed alongside producer surplus, which measures gains to sellers. Together they form total surplus in a basic market model. Taxes, binding price controls, and restrictions on trade can change these areas and may reduce total gains from exchange.