Consumer surplus

Consumer surplus or Consumer's surplus (or in the plural Consumers' surplus) is the difference between the price consumers they are willing to pay (or reservation price) and the actual price. If someone is willing to pay more than the actual price, their benefit in a transaction is how much they saved when they didn't pay that price. For example, a person is willing to pay a tremendous amount for water since he needs it to survive, however since there are competing suppliers of water he is able to purchase it for less than he is willing to pay. The difference between the two prices is the consumer surplus.