What is contribution margin?

What is the contribution margin formula?

Contribution margin is revenue minus variable costs. The contribution margin ratio is that amount divided by revenue. The Corporate Finance Institute defines the ratio as revenue less all variable costs, divided by revenue, and leaves fixed costs out.

Contribution margin = price − variable costs per order
Contribution margin ratio = contribution margin ÷ price

Which costs are variable?

Variable costs rise with each order. Fixed costs do not.

Worked example

These are the example numbers the contribution margin calculator uses.

• Contribution margin = 150 − 90 = 60 per order.
• Contribution margin ratio = 60 ÷ 150 = 0.40, or 40 percent.

How is contribution margin different from gross margin?

Gross margin usually subtracts only the cost of goods. Contribution margin also subtracts shipping, payment fees and other per-order costs, so it is lower and closer to what an order really leaves. For ad decisions, contribution margin is the safer number: using gross margin makes break-even ROAS look lower than it is.

How does it set your ad limits?

Two break-even numbers come straight from contribution margin:

• Break-even CPA = contribution margin per order = 60. Paying more than 60 in ads for one order loses money on it.
• Break-even ROAS = 1 ÷ ratio = 1 ÷ 0.40 = 2.5.

Why does it matter for AI and UGC ads?

Contribution margin decides how much room a creative has to work. A brand with a 0.70 ratio breaks even at a ROAS of about 1.43, so many AI versions can pass the bar. A brand with a 0.25 ratio needs a ROAS of 4.0, so only the strongest versions survive. Knowing the number before briefing creators means every version is judged on the same line.

Raising the margin, through price, bundles or cheaper shipping, lowers break-even ROAS for every ad at once. Better creative lowers CPA one ad at a time. Both show up in lifetime value too, when it is calculated on profit.