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Contribution Margin

Contribution Margin

Contribution margin is the money left from a sale after subtracting all variable costs, the costs that grow with each order, such as product cost, shipping, payment fees and often marketing. It shows how much each sale contributes toward fixed costs and profit.

Revenue tells you how much came in. Contribution margin tells you how much of it you actually get to keep for each sale. For e-commerce brands and anyone running paid ads, it is the number that turns marketing metrics like ROAS and CPA into profit decisions.

How Do You Calculate Contribution Margin?

The formula is: contribution margin = revenue - variable costs. As a ratio: contribution margin % = contribution margin / revenue.

Say an order is worth $100. Product cost is $35, shipping and packaging $10, payment fees $3. Contribution margin before marketing is $52, or 52%. If the ad spend to win that order was $30, contribution margin after marketing is $22.

Gross Margin vs Contribution Margin

Gross margin subtracts only the cost of goods sold. Contribution margin also subtracts the other costs that rise with every order, like shipping, fees and returns. That makes contribution margin a more honest view of what a sale is worth, especially for brands with heavy shipping or high return rates.

Why Contribution Margin Matters in Marketing

  • Break-even ROAS: divide 1 by your contribution margin before marketing. At 52%, you break even at a ROAS of about 1.9.
  • Maximum CPA: the contribution margin per order before marketing is the most you can spend to acquire it without losing money on the first purchase.
  • Scaling decisions: brands that track contribution margin after marketing can see whether more spend is still adding profit, not just revenue.

Contribution Margin and MER

MER compares total revenue with total marketing spend. Contribution margin tells you what MER you need. If your contribution margin before marketing is 50%, a MER of 2 means marketing is consuming all of it, and you need a MER comfortably above that to make a profit.

Frequently asked questions

What is contribution margin?+

Contribution margin is revenue minus variable costs, such as product cost, shipping and payment fees. It is what each sale contributes toward fixed costs and profit.

What is the difference between gross margin and contribution margin?+

Gross margin subtracts only the cost of goods sold. Contribution margin also subtracts other per order costs like shipping, fees and returns, and often marketing.

How does contribution margin relate to ROAS?+

Your break-even ROAS is 1 divided by your contribution margin before marketing. A 40% margin means you need a ROAS of 2.5 just to break even.

Related terms

MER

Marketing Efficiency Ratio

MER (Marketing Efficiency Ratio) is a metric that measures total company revenue against total marketing spend across all channels. Unlike channel-level ROAS, it takes a blended, business-wide view of whether marketing as a whole is producing revenue efficiently.

ROAS

Return on Ad Spend

ROAS (Return on Ad Spend) is a marketing metric that measures how much revenue a business earns for every dollar it spends on advertising. It is calculated by dividing the revenue attributed to your ads by the cost of those ads.

AOV

Average Order Value

AOV (Average Order Value) is the average amount a customer spends in a single order. It is calculated by dividing total revenue by the number of orders over a given period, and it is a core metric for understanding and improving e-commerce profitability.