Consumer Surplus

  • This is the difference between the price a consumer is willing to pay and the price he actually pays.
  • For example if you were willing to buy a computer game for £50, but can buy it for £15 in the sales your consumer surplus is £35

Diagram Consumer and Producer Surplus


  • Consumer Surplus is therefore the difference between the demand curve and the market price.
  • We can also explain consumer surplus by using marginal utility. This is the utility you gain from consuming an extra unit of a good. If the Marginal utility is greater than the price, the difference is your consumer surplus.
  • The demand curve is derived from our marginal utility. (see: marginal utility theory)
  • A Person’s Consumer Surplus from Petrol


    In the above diagram, at Q 500 litres, the MU is 80p > than the price = 50p.

Producer Surplus

  • This is the difference between the price a firm receives and the price it would be willing to sell it at.
  • Therefore it is the difference between the supply curve and the market price