Contribution Margin for E-commerce: Formula, Examples and Benchmarks

Two stores both sell $1 million a year. One makes $150,000 in profit. The other loses $50,000. Same revenue, very different businesses. The difference almost always shows up in one number: contribution margin.

Revenue tells you how big you are. Contribution margin tells you whether getting bigger is a good idea.

Try the calculator above with your own numbers. Then read on for what each result means.

What is contribution margin?

Contribution margin is the money each sale leaves behind after paying every cost that comes with that sale. It is what “contributes” toward your fixed costs (staff, rent, software) and, after those, your profit.

The key word is variable. A variable cost only exists because you made a sale: the product itself, the box, the shipping label, the payment fee. Fixed costs stay the same whether you sell 10 orders or 10,000.

The contribution margin formula

Contribution margin = revenue − variable costs

Contribution margin ratio = (revenue − variable costs) ÷ revenue

In e-commerce, variable costs typically include:

• Cost of goods sold (COGS)
• Shipping and fulfillment (pick, pack, packaging)
• Payment processing fees
• Returns, refunds and chargebacks
• Marketing spent to win the order

CM1, CM2 and CM3: three levels that tell you different things

Most e-commerce operators split contribution margin into three levels. Each one answers a different question.

Example: one $80 order

This store keeps $18.60 per order to pay for its team, tools and profit. That’s healthy. But notice how the picture changes level by level. A 65% gross margin sounds luxurious. After everything, less than a quarter remains.

Why contribution margin matters more than revenue

It shows whether growth is worth it. If CM3 is negative, every new customer costs you money. Spending more on ads only makes the hole deeper, unless those customers come back and buy again.

It sets your ad budget. CM2 is the most you can pay to win an order and still break even. That’s where break-even ROAS comes from: 1 ÷ CM2 ratio. In the example, 1 ÷ 0.51 ≈ 1.97x.

It ranks your products honestly. Your bestseller by revenue is often not your best product by contribution margin. Heavy, cheap or frequently returned items can look great in sales reports and still drag profit down.

What is a good contribution margin in e-commerce?

There’s no universal answer, but these ranges hold for most DTC brands:

Resellers and dropshippers typically run lower CM1, often 25–40%, which leaves very little room for paid acquisition.

Contribution margin vs gross margin

Gross margin is CM1 by another name: revenue minus product cost. It’s useful for pricing, but it ignores everything that happens after the product leaves the shelf.

Shipping, fees and returns can easily eat 15–20% of revenue. A store judging itself on gross margin will overestimate how much it can spend on ads, and that’s how a store with “great margins” ends up losing money.

How to improve contribution margin

1. Raise average order value. Shipping and fulfillment are partly fixed per order, so bigger baskets dilute them.
2. Price by contribution, not competitors. Know what each SKU leaves behind before you match a rival’s price.
3. Fix your return rate. Clear sizing, honest photos and better descriptions directly recover margin.
4. Shift ad spend to high-margin products. Promote what makes money per order, not just what sells fastest.
5. Renegotiate the boring stuff. Packaging, carrier rates and payment fees compound across thousands of orders.

The short version

• Contribution margin = revenue − every cost that comes with the sale.
• Track three levels: CM1 for pricing, CM2 for operations, CM3 for growth.
• CM2 sets your break-even ROAS. CM3 tells you if growth pays.
• Rank products and campaigns by contribution margin, not revenue.

Calculate yours with the contribution margin calculator, then see the whole picture in the profit margin calculator.