How to calculate contribution margin
Contribution margin isolates the profitability of each sale before fixed costs. It answers how much money a sale contributes toward covering overhead and generating profit.
It differs from gross margin in which costs it subtracts: contribution margin removes all variable costs, while gross margin removes cost of goods sold. The two overlap but are not identical.
- Revenue - variable costs The formula
- Per unit or total Two views
- Covers fixed costs What it funds
Short answer
Contribution margin is revenue left after variable costs, available to cover fixed costs and profit. Subtract variable costs from revenue, per unit or in total. If a product sells for 100 dollars with 30 dollars of variable cost, the contribution margin is 70 dollars, or 70 percent. It shows how much each sale contributes toward fixed costs and profit.
Step by step
Identify variable costs
List the costs that scale with each sale: cost to serve, payment processing, usage-based infrastructure, and variable support. Exclude fixed costs like salaries and rent.
Subtract from revenue
Contribution margin equals revenue minus variable costs, computed per unit or across total sales.
Express as a percentage
Contribution margin percentage equals contribution margin divided by revenue, times 100.
Use it for break-even
Divide total fixed costs by contribution margin to find how many units or how much revenue you need to break even.
Worked example
A subscription sells for 1,000 dollars a month. Variable costs, hosting, processing, and variable support, total 250 dollars. Contribution margin is 750 dollars, or 75 percent.
If your fixed costs are 300,000 dollars a month, you need 300,000 divided by 750, or 400 subscriptions, to break even. Contribution margin is what turns fixed-cost coverage into a concrete unit target.
How Ardovo handles it
Ardovo can surface contribution margin by product and segment, so you see which lines actually contribute to covering fixed costs. Rook flags segments whose contribution margin is thin despite healthy revenue, pointing to a cost-to-serve problem.
Frequently asked questions
What is the contribution margin formula?
Revenue minus variable costs, per unit or in total. As a percentage, it is contribution margin divided by revenue, times 100. It shows how much each sale contributes toward covering fixed costs and profit.
What is the difference between contribution margin and gross margin?
Contribution margin subtracts all variable costs; gross margin subtracts cost of goods sold. They overlap but differ, because some COGS can be fixed and some variable costs sit outside COGS. Contribution margin is more precise for break-even analysis.
Why is contribution margin useful?
Because it reveals how much each sale contributes toward fixed costs and profit, which drives break-even analysis and pricing decisions. Dividing fixed costs by contribution margin gives the exact volume needed to break even.