Consumer SurplusThe demand curve for computers is smooth because there are many potential buyers. At a price of $1,500, 1 million computers are demanded. The consumer surplus at this price is equal to the shaded area: the area below the demand curve but above the price. The area of a triangle is ½ × the base of the triangle × the height of the triangle. So the total consumer surplus in this case is ½ × 1 million × $3,500 = $1.75 billion. This is the total net gain to consumers generated from buying and consuming computers when the price is $1,500.