Find a calculator ↗Contribution Margin Calculator
Use this contribution margin calculator to find the amount each sale leaves after variable costs. Calculate contribution per unit, contribution margin percentage, and total contribution before fixed expenses.
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What is contribution margin?
This contribution margin calculator helps you find the amount each sale leaves after variable costs.
Contribution margin is sales revenue left after variable costs. It shows what remains to cover fixed operating costs and, after those are covered, profit. The per-unit figure is useful for evaluating a product or a consistent service unit.
Contribution margin is not gross margin
Gross margin follows the costs included in your accounting cost of goods sold. Contribution margin classifies costs by how they change with volume. Depending on the business, the two measures can differ.
How to use the contribution calculator
Enter the net selling price, variable cost per unit, any additional percentage selling fee, and units sold. Keep revenue and costs on a consistent tax and discount basis.
Classify costs carefully
Include costs that change with the sales volume being modeled. A flat monthly software subscription is usually not a per-unit variable cost over a small volume range, while a per-transaction fee is. Cost behavior can change when capacity limits are reached.
Step-by-step planning checklist
- Choose a product or a clearly defined service unit.
- Record the actual net price after discounts and identify costs that change when another unit is sold.
- Keep percentage fees separate from costs already included per unit.
- Compare the resulting total contribution with the fixed expenses for the same sales period.
Formula and worked example
At a $100 selling price, $60 variable unit cost, and a 3% selling fee, each unit carries $63 of variable cost. Contribution is $37 per unit and the contribution margin ratio is 37%. Selling 1,000 units generates $100,000 revenue and $37,000 contribution before fixed costs.
Avoid counting fees twice
If payment processing is already included in the $60 variable cost, leave the separate fee field at zero or remove it from the unit-cost input.
Use contribution to evaluate a decision
Compare a price discount, a supplier-cost increase, or a channel with different fees. A positive contribution can support fixed costs, but a low ratio means more sales are needed to cover them. Follow this calculation with the break-even calculator for a volume target.
Limits and capacity effects
The model assumes one consistent unit and stable costs. It does not allocate fixed expenses, predict demand, or account for a changing product mix. Negative contribution means selling more under the same terms worsens the modeled economics rather than solving the problem.
Further reading: U.S. Small Business Administration break-even guidance.
Frequently asked questions
Is contribution the same as profit?
No. Fixed expenses, taxes, financing, and other excluded costs still need to be covered.
For example, $37,000 of contribution with $30,000 of fixed costs leaves $7,000 before other excluded expenses. Without the fixed-cost figure, contribution alone cannot establish profitability.
Can this be used for a service?
Yes, if you define a consistent service unit and identify the costs that vary with that unit.
A unit could be one installation or one standard service package. Where delivery effort varies widely, calculate separate scenarios instead of relying on a single average.
What does a negative contribution mean?
The price is below the entered variable costs, so each additional unit reduces contribution.
Check whether a discount, fee, or delivery cost caused the negative result. Selling more at the same economics will not repair the shortfall.
Should sales tax be included in the price?
Use a consistent net-revenue basis; this calculator does not calculate sales tax.
Enter the revenue the business retains from a sale and apply the same basis to variable expenses. Do not treat money collected for tax remittance as extra contribution.
Can I combine several products?
A single average can hide product differences. Calculate each product separately or use a clearly defined, stable sales mix.
Use the same product mix when comparing periods. Otherwise, a margin change may reflect the mix rather than a change in individual product economics.
Related tools and categories
Business Break-Even Calculator
Find the sales volume needed to cover fixed operating costs or reach a chosen profit target. Use a consistent product unit and a single planning period.
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