A contribution margin income statement is an income statement in which all variable expenses are deducted from sales to arrive at a contribution margin. Then, all fixed expenses are subtracted to arrive at the net profit or net loss for the period. Thus, the arrangement of expenses in the income statement corresponds to the nature of the expenses.
In essence, if there are no sales, a contribution margin income statement will have a zero contribution margin, with fixed costs clustered beneath the contribution margin line item. As sales increase, the contribution margin will increase in conjunction with sales, while fixed expenses remain (approximately) the same. Fixed expenses will increase if there is a step cost situation, where a block of expenses must be incurred to meet the requirements of an increase in activity levels. For example, sales may increase so much that an additional production facility must be opened, which will call for the incurrence of additional fixed costs.
The contribution margin income statement is a superior form of presentation, because the contribution margin clearly shows the amount available to cover fixed costs and generate a profit (or loss). It is useful to create an income statement in the contribution margin format when you want to determine that proportion of expenses that truly varies directly with revenues. In many businesses, the contribution margin will be substantially higher than the gross margin, because such a large proportion of its production costs are fixed, and few of its selling and administrative expenses are variable.
A contribution margin income statement varies from a normal income statement in three ways. First, fixed production costs are aggregated lower in the income statement, after the contribution margin. Second, variable selling and administrative expenses are grouped with variable production costs, so that they are part of the calculation of the contribution margin. And finally, the gross margin is replaced in the statement by the contribution margin.
Under both the contribution margin income statement and a normal income statement, the net profit or loss will be the same, because all revenue and expense items are included in both formats; only their order of presentation differs.