Consumer surplus is defined as the highest price consumers are willing to pay for a good minus the price actually paid. If a consumer was willing to pay more than the market price, then they have a surplus (more satisfaction). If a consumer was willing to pay less than the market price, then they were not a part of the market.
Consumer surplus is the area below demand and above the price line.
Producer surplus is defined as the price recieved by firms for selling their good minus the lowest price that they are willing to accept to produce the good. The lowest price they are willing to accept represents the firm’s cost of producing an extra unit of the good (or marginal cost), and is shown by the supply curve.
Producer surplus is the area below the price line and above the supply curve.