Contribution Margin Ratio Calculator
The contribution margin ratio tells you how much of each sales dollar is left after variable costs to cover fixed costs and add to profit. It is the heart of cost-volume-profit analysis and the quickest route to a break-even figure. This calculator takes the selling price per unit, the variable cost per unit, the units sold, and total fixed costs, then returns the contribution margin per unit, the contribution margin ratio, total contribution margin, and break-even sales in dollars. Enter your own product and cost figures.
Contribution margin ratio formula
Contribution margin per unit = price - variable cost per unit
Contribution margin ratio = contribution margin per unit / price
Total contribution margin = (price - variable cost) * units
Break-even sales = fixed costs / contribution margin ratio
The contribution margin ratio is the same whether computed per unit or on totals, as long as the product mix is constant. Break-even sales is the revenue at which total contribution margin exactly covers fixed costs.
Using the contribution margin ratio
- It isolates how much each sales dollar contributes beyond variable costs.
- A higher ratio means fixed costs are covered with fewer sales dollars.
- Break-even sales equal fixed costs divided by the ratio.
- It supports pricing, product-mix, and make-or-buy decisions.
- Above break-even, profit rises by the ratio times each extra sales dollar.
Contribution margin ratio: frequently asked questions
What is the contribution margin ratio?
The contribution margin ratio is the share of each sales dollar that remains after variable costs and is available to cover fixed costs and profit. It equals contribution margin divided by sales, where contribution margin is sales minus variable costs. A 40 percent ratio means 40 cents of every sales dollar contributes toward fixed costs and profit.
What is the contribution margin ratio formula?
Contribution margin per unit = price - variable cost per unit. Contribution margin ratio = contribution margin per unit / price, or equivalently total contribution margin / total sales. Total contribution margin = (price - variable cost) * units sold.
How does it relate to break-even?
Break-even sales in dollars equals fixed costs divided by the contribution margin ratio. Break-even units equal fixed costs divided by the contribution margin per unit. Above break-even, each additional dollar of sales adds its contribution margin ratio to profit.
Why is the contribution margin ratio useful?
It shows how much each sales dollar contributes to covering fixed costs and generating profit, independent of volume. Managers use it for break-even analysis, pricing decisions, and assessing which products contribute most per dollar of sales when capacity is the constraint.
What inputs does this calculator use?
Enter the selling price per unit, the variable cost per unit, the number of units sold, and total fixed costs. The calculator returns the contribution margin per unit, the contribution margin ratio, total contribution margin, and the break-even sales in dollars.
Official sources
- U.S. Small Business Administration: Manage your finances.
- U.S. Small Business Administration: Calculate your startup costs.
Reviewed by the CalculatorHub team, edited by James Graham, 16 June 2026. See our methodology.