Contribution Margin

Contribution margin is revenue minus all variable costs (COGS plus variable sales and marketing plus variable customer-success), expressed as a percentage of revenue. It provides a view of unit profitability that accounts for the full cost of serving each customer rather than just delivery costs (gross margin). The metric is particularly useful at marketplace and consumer companies where variable costs go well beyond COGS, and less commonly used at SaaS companies where most non-COGS costs are fixed at scale. Contribution margin is the deeper unit-economics view that gross margin alone can miss.

The calculation:

Basic formula:

• Contribution Margin = (Revenue - Variable Costs) / Revenue
• Variable Costs = COGS + Variable S&M + Variable Customer Success + Other Variable

What's variable (depends on business):

For marketplaces and transactional businesses:

• Payment processing fees.
• Customer acquisition costs (advertising tied to acquiring users).
• Variable customer support per transaction.
• Fulfillment, shipping, delivery (for physical).

For consumer subscription:

• Streaming costs per user (Netflix, Spotify content licensing).
• Variable customer support per active user.
• Payment processing.

For SaaS (typically less variable cost):

• Hosting and infrastructure (often a flat function of usage; can be variable).
• Variable customer success (occasional; usually fixed at scale).
• Most other costs (sales, marketing, G&A) are fixed at scale.

Contribution margin vs gross margin:

Gross margin: revenue minus COGS only. Excludes variable sales/marketing/customer-success.

Contribution margin: revenue minus all variable costs including S&M and customer success.

At SaaS companies: gross margin and contribution margin are often similar because most non-COGS costs are fixed.

At marketplaces and consumer: contribution margin can be significantly lower than gross margin because acquisition and per-transaction costs are real variable expenses.

Why contribution margin matters:

True unit economics: shows whether the business model works at the per-customer level after all variable costs.

Profitability ceiling: total profitability = (Contribution Margin × Revenue) - Fixed Costs. Contribution margin determines the ceiling.

Pricing decisions: pricing changes affect contribution margin directly; analyzing impact requires variable-cost view.

Channel and segment analysis: different channels and segments have different contribution margins; investment should flow to highest contribution.

What founders get wrong: Focusing on gross margin when contribution margin is the more relevant metric for the business model. The right discipline: at marketplaces and consumer, track contribution margin (gross margin minus variable S&M and customer success). At SaaS, the two metrics are often close. Either way, understand which matters for your model.

Related: Gross Margin · P and L Statement · Unit Economics · CAC · Financial Model

FAQ

What is contribution margin?
Revenue minus all variable costs (COGS plus variable sales and marketing plus variable customer success), expressed as a percentage of revenue. Provides a view of unit profitability accounting for the full cost of serving each customer.

How does contribution margin differ from gross margin?
Gross margin is revenue minus COGS only. Contribution margin is revenue minus all variable costs (including variable S&M and customer success). At SaaS the two are often similar; at marketplaces and consumer they can diverge significantly.

When does contribution margin matter most?
At marketplaces (significant payment and acquisition costs), consumer subscriptions (content licensing, support), and transactional businesses. At pure SaaS, contribution margin and gross margin are often close so the distinction matters less.