Identify the demand curve or demand equation
Find the market price paid by consumers
Determine the quantity purchased at that price
Calculate the maximum price consumers are willing to pay for each unit from the demand curve
Compute the area between the demand curve and the market price line up 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 minus market price
For a demand equation, integrate the demand curve from 0 to the purchased quantity and subtract price × quantity
Consumer Surplus = ∫ from 0 to Q of Demand Price dQ – P × Q