You ran a 20% off sale. Did you actually make money?

Contribution Margin: The Number Every Ecommerce Sale Should Be Measured Against

A successful promotion feels great. Orders increase, revenue jumps, and your bank account receives a larger deposit. But one important question often goes unanswered:

Did the sale actually make money?

This webinar explains why ecommerce businesses should evaluate promotions using contribution margin, not just revenue or gross sales. A 20% discount may increase order volume, but if fees, advertising costs, fulfillment expenses, and discounts aren't included in the calculation, the campaign may be far less profitable than it appears.

The session begins with a simple example. A product sells for $100 with a cost of goods sold (COGS) of $60, creating a $40 gross margin. After offering a 20% discount, the selling price falls to $80 while COGS remains unchanged. The customer's discount is 20%, but the seller's profit is cut by 50%. That difference is often overlooked when businesses plan promotions.

The webinar then introduces the additional costs that many sellers forget to include. Marketplace fees, payment processing, advertising spend, and discounts on products that would have sold anyway all reduce profitability. Looking only at revenue hides these expenses and creates a false sense of success.

A key takeaway is that contribution margin tells a much more complete story than revenue alone. In the example, unit sales increase significantly during the promotion, yet once all expenses are considered, the increase in profit is far smaller than expected. Revenue rises, but contribution margin reveals whether the campaign truly improved the business.

The webinar also introduces the concept of a maximum profitable discount or "margin floor." By understanding product margins, marketplace fees, and cost of goods sold, sellers can calculate the largest discount they can offer before the promotion starts destroying profitability. This provides a repeatable framework for planning future sales instead of relying on intuition.

That doesn't mean every promotion should maximize profit. Prime Day, Black Friday, product launches, or inventory clearance campaigns may intentionally sacrifice short-term margins to gain new customers or free up cash. The important point is that these decisions should be intentional and supported by accurate financial data rather than optimistic revenue numbers.

Finally, the webinar explains why order-level reconciliation is essential for ecommerce businesses. When every order, fee, payout, advertising expense, and cost is automatically recorded in QuickBooks, sellers can accurately measure contribution margin for every promotion. Ecommerce accounting automation helps replace guesswork with reliable financial reporting, making it easier to decide which discounts grow the business and which simply increase sales without increasing profit.