Profit Margin

What Is Margin?

Margin is the difference between selling price and the cost of delivering the product, expressed as a currency amount or percentage. In ecommerce, the most useful operating metric is contribution margin: price minus product, shipping, packaging, payments, returns, discounts, and variable support costs. Only from that amount can you pay for ads and keep profit.

The online market is growing, but growth does not cancel math. Shopify reports online sales are set to reach $6.88 trillion in 2026 and 21.1% of total retail sales (source: https://www.shopify.com/blog/global-ecommerce-sales). At the same time, Meta reported a 12% year-over-year increase in average price per ad in Q1 2026 (source: https://www.prnewswire.com/news-releases/meta-reports-first-quarter-2026-results-302757852.html). If margin is too low, a growing market only lets you burn a larger budget faster.

Example: you sell a product for 179 PLN. Product cost is 52 PLN, shipping 18 PLN, packaging 4 PLN, payment and platform fees 7 PLN, expected returns and support 10 PLN. Variable cost is 91 PLN, so contribution margin is 88 PLN. If CPA is 60 PLN, you keep 28 PLN. If CPA is 95 PLN, you lose 7 PLN per order. Revenue looks good, but margin decides whether you can scale.

Percentage margin is calculated as (price - cost) / price x 100%. In this example, 88 / 179 = 49.2% contribution margin before ads. This is not the same as markup. If you buy for 50 PLN and sell for 100 PLN, markup is 100%, but margin is 50%. Confusing these two terms leads to overly aggressive ad budgets.

An operator should have a margin calculator for every product and bundle. Include normal, pessimistic, and scaling scenarios: higher CPM, higher refund rate, discount, influencer code, more expensive shipping. A product fit for ads needs room for error. If profit disappears after a small CPA increase, it is not a scaling product; it is a cautious test or an offer that needs improvement.

Review margin over time, not only before launch. A supplier can raise price, currency can move, returns can exceed assumptions, and promotions can train customers to wait for discounts. Once a month, compare planned margin with actual order margin. If the gap is more than a few percentage points, update CPA and ROAS thresholds. Old assumptions are one of the most common reasons stores scale losses.

For bundles, recalculate margin from scratch. A bundle often has better AOV, but it may need a larger box, more expensive shipping, higher picking cost, or a bigger discount. If you treat it like a single product, you overstate profitability. Keep separate cost, CPA threshold, and breakeven ROAS for every offer variant. It is boring, but it prevents false scaling.