Contribution margin measures revenue left after variable costs of fulfillment, expressed in dollars or as a percentage of revenue.

How it works

Define variable costs per customer or order: COGS, usage-based infrastructure, shipping, variable support, payment processing. Contribution margin dollars equal revenue minus those variable costs; contribution margin percent divides by revenue. Example pattern: if a subscription is $100/month and variable delivery cost is $30, contribution margin is $70 (70%). Fixed costs—R&D, GTM salaries, office—sit below this line for operating profit analysis. SaaS often discusses gross margin similarly; contribution margin sometimes isolates a SKU or segment. Investors stress-test contribution margin at scale assumptions—do variable costs rise with usage faster than price?

Why it matters

• Founders: Pricing and packaging must cover variable costs with room for CAC payback. Negative contribution margin cannot be fixed by volume alone.
• Investors: Efficient growth requires healthy contribution margin to fund acquisition and overhead. Consumption models need tight variable cost discipline.
• Operators: Product and finance align on which costs are truly variable for decision-making—not every COGS line scales equally.

Common mistake

Treating all engineering spend as fixed while ignoring variable support or success costs tied to revenue—overstates contribution margin.

Related ideas

Gross margin, contribution profit, unit economics, COGS, and CAC payback build on contribution margin analysis.