How to Calculate Contribution Margin?

Contribution margin helps in studying how revenue or sales affect profits or net income. It is expressed as a percentage, and we can calculate the contribution margin ratio by subtracting sales from variable expenses and dividing it by sales. Basically, it tells the marginal benefit of making or producing one more unit. In absolute terms, it represents the earnings available to pay for the fixed expenses.

We can calculate contribution margin in three forms – In total, Per unit, and As a ratio. All three forms together help us understand how different factors – sales price, sales volume, variable costs, and fixed costs – connect to each other. Thus, they allow managers and management to make better decisions regarding sales and costs.

Three Forms of Calculating Contribution

Lets’ understand the three forms in detail:

How to Calculate Contribution Margin In total?

This measures the absolute amount of contribution margin that a company enjoys. The formula for Total contribution margin is Total sales, Less Total variable costs. One can use this to determine overall profitability by comparing the total margin to fixed costs. Net income for a company will be the contribution margin, Less fixed costs.

One can also use the contribution margin to prepare a contribution margin income statement. This statement helps understand how sales will affect profitability and cost behavior. Amounts, such as sales, variable costs, and contribution margin, change in proportion to each other. For instance, if sales increase by 10%, then contribution margin and variable costs would also rise by 10%. The fixed costs, however, remain the same.

The contribution margin income statement is different from the income statement. We first subtract variable costs from sales and then fixed costs in the contribution margin income statement. In this, variable and fixed cost includes both manufacturing and selling costs. Following is a proforma of a contribution margin income statement

ParticularsAmt ($)
Less: Variable Cost1,000
Contribution Margin1,000
Less: Fixed Cost500
Operating Income500
Less: Provision for Income Tax200
Net Income300
How to calculate Contribution Margin?

How to Calculate Contribution Margin Per unit?

Calculating per unit of contribution margin tells how sales of additional units impact the net income. We can calculate it by subtracting the sales price per unit from the variable costs per unit. For example, a smartphone sells for $1000, and the variable cost of each unit is $600. In this case, the contribution margin per unit is $400, or we can say selling each unit increase the net income by $400. We can also say that any increase in the selling price won’t affect the variable cost and thus would lead to more profits only.

How to Calculate Contribution Margin Ratio?

When we calculate the contribution margin ratio, it tells the percentage of sales that would help to increase the net income. To calculate the contribution margin ratio, we divide the contribution margin by sales. The contribution margin or sales can either be total or per unit. The formula for contribution margin ratio is;

Total contribution margin / Total sales or Contribution margin per unit / Sales price per unit

Lets’ understand the concept with the help of a formula. Suppose a machine sells for $1000, while its variable cost is $500. The contribution margin, in this case, is 50%.

To understand how the sales will affect the net income, all we need to do is multiply the margin ratio by the sales amount. In the above example, we can say that the $1000 sales increase the net income by $400.


Let us understand all three forms of contribution margin with the help of a simple example. Company A has net sales of $300,000 after selling 50,000 units of its products. The variable cost per unit is $2.

In this example, the selling price per unit will be $6 ($300,000 / 50,000). So, the contribution margin per unit will be $4 (Selling price per unit – Variable cost per unit).

Now, Contribution would be $200,000 ($4 * 50,000), while the contribution margin ratio is 66.67% (Contribution / Sales).

Error to Look for When you Calculate Contribution Margin

One common mistake that many make while calculating the contribution margin is that they wrongly classify the fixed and variable costs. Thus, to avoid such errors and accurately calculate the ratio, it is imperative to understand what the company classifies as a fixed or variable cost.

Sometimes, however, it gets difficult to classify certain items. For instance, a company buys software to boost production on a temporary basis. One can classify it either as a variable or fixed cost. Variable cost because it is directly related to the production, and fixed cost because it is a one-time investment.

It will be correct to put it in either head, but the company should give proper information. Also, it must ensure that the current treatment of the item is in line with the previous treatment of the same item, or the company should treat it the same way in the future.

Quiz on Contribution margin

This quiz will help you to take a quick test of what you have read here.

Sanjay Borad

Sanjay Bulaki Borad

MBA-Finance, CMA, CS, Insolvency Professional, B'Com

Sanjay Borad, Founder of eFinanceManagement, is a Management Consultant with 7 years of MNC experience and 11 years in Consultancy. He caters to clients with turnovers from 200 Million to 12,000 Million, including listed entities, and has vast industry experience in over 20 sectors. Additionally, he serves as a visiting faculty for Finance and Costing in MBA Colleges and CA, CMA Coaching Classes.

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