Unit Economics

Contribution Margin

Definition

Contribution margin is the revenue remaining after subtracting variable costs directly associated with producing and delivering a product or service. Expressed as a dollar amount or percentage, it shows how much each unit sold contributes toward covering fixed costs and generating profit.

Formula

Contribution Margin = Revenue − Variable Costs Contribution Margin Ratio = (Revenue − Variable Costs) ÷ Revenue × 100

Overview

Contribution margin isolates the profit from each unit sold after covering only the variable costs tied to that unit. Unlike gross margin (which uses COGS), contribution margin can include variable selling costs like payment processing fees, sales commissions, and per-transaction support costs.

For SaaS businesses, contribution margin is particularly useful when evaluating individual product lines, pricing tiers, or customer segments. A plan with high revenue but thin contribution margin may not be worth promoting if it barely covers its variable costs.

The contribution margin ratio (contribution margin ÷ revenue) determines how much each additional dollar of revenue contributes to fixed cost coverage and profit. A higher ratio means the business reaches its break-even point faster and generates more profit from each incremental sale beyond that point.

Example

A $200/month subscription with $30 in variable costs (hosting, payment processing, support) has a contribution margin of $170 and a contribution margin ratio of 85 %.

Profit Margins by Industry: 2026 Benchmarks and How to Improve Yours Break-Even Analysis: How to Know When Your Product Will Start Making Money