Find the demand curve or demand equation
Identify the market price paid per unit
Determine the quantity purchased at that price
Find the maximum price consumers are willing to pay for each unit up to that quantity
Calculate the area between the demand curve and the market price line from 0 to the quantity purchased
Use the formula: Consumer Surplus = Total willingness to pay – Total amount actually paid
For a linear demand curve, use: Consumer Surplus = 1/2 × base × height
Base = quantity purchased
Height = maximum willingness to pay at zero quantity – market price
For a demand equation, integrate the demand curve above the price from 0 to quantity
Consumer Surplus = ∫ from 0 to Q of [Demand Price(q) – Market Price] dq