Contribution margin is a product’s price minus all associated variable costs, resulting in the incremental profit earned for each unit sold. The total contribution margin generated by an entity represents the total earnings available to pay for fixed expenses and to generate a profit.
The contribution margin concept is useful for deciding whether to allow a lower price in special pricing situations. If the contribution margin at a particular price point is excessively low or negative, it would be unwise to continue selling a product at that price. It is also useful for determining the profits that will arise from various sales levels (see the example). Further, the concept can be used to decide which of several products to sell if they use a common bottleneck resource, so that the product with the highest contribution margin is given preference.
The contribution margin concept can be applied throughout a business, for individual products, product lines, profit centers, subsidiaries, distribution channels, sales by customer, and for an entire business.
To determine the contribution margin, subtract all variable costs of a product from its revenues, and divide by its net revenue. Product variable costs typically include, at a minimum, the costs of direct materials and sales commissions. The calculation is:
(Net product revenue - Product variable costs) ÷ Product revenue
For example, the Iverson Drum Company sells drum sets to high schools. In the most recent period, it sold $1,000,000 of drum sets that had related variable costs of $400,000. Iverson had $660,000 of fixed costs during the period, resulting in a loss of $60,000.
Iverson’s contribution margin is 60%, so if it wants to break even, it needs to either reduce its fixed expenses by $60,000 or increase its sales by $100,000 (calculated as $60,000 loss divided by 60% contribution margin).
When using this measurement, be aware that the contribution margin does not account for the impact of a product on the bottleneck operation of a company. A low contribution margin may be entirely acceptable, as long as it requires little or no processing time by the bottleneck operation.