Producer SurplusHere is the supply curve for wheat. At a price of $5 per bushel, farmers supply 1 million bushels. The producer surplus at this price is equal to the shaded area above the supply curve but below the price: ½ × 1 million × $4 = $2 million. This is the total gain to producers—farmers in this case—from supplying their product when the price is $5.