Contribution Margin CalculatorWhat you actually keep from each sale
Contribution margin is revenue minus every cost that comes with each order: product cost, marketplace and payment fees, shipping, packaging, returns and ad spend. It has to be positive before you can cover fixed costs.
Enter your own channel and payment fees. Defaults are reference values from public pages as of November 2026.
Connect orders, ad spend and product costs, and Laplace calculates contribution margin and real ROAS for every product every day, including bundle and gift costs.
How the contribution margin is calculated
- STEP 1
Contribution margin = revenue − variable costs
Revenue is what the customer pays (price − seller-funded discount + shipping charged). Variable costs are COGS, fees, shipping, packaging, expected return losses and ad spend.
- STEP 2
Contribution margin ratio = contribution ÷ revenue
At the same revenue, putting ad budget behind higher-ratio products leaves more profit.
- STEP 3
Pre-ad contribution is your max CPA
It is the most you can spend to acquire one order without losing money.
Worked example
Result with the calculator's default inputs.
| Sale price | $39.00 |
|---|---|
| COGS | −$11.00 |
| Fees (Custom) | −$3.90 |
| Shipping | −$6.50 |
| Packaging & returns | −$1.42 |
| Ad spend (ROAS 300%) | −$13.00 |
| Contribution | $3.18 |
| Contribution margin | 8.2% |
| Break-even ROAS | 241% |
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FAQ
How is contribution margin different from gross margin?
Gross margin only subtracts product cost. Contribution margin also subtracts fees, shipping and ad spend, so it shows what each order really leaves. This calculator shows contribution before and after ads.
Should ad spend be included?
Yes. In ecommerce, ads are usually the largest per-order variable cost. Contribution after ads tells you whether growth is profitable.
Do you store the numbers I enter?
No. Everything is calculated in your browser, and there is no sign-up or email gate. 'Copy result link' puts your inputs in the URL, so only people with that link see the same result.
Do I have to calculate every SKU by hand?
This calculator is for one product at a time. Laplace Analytics connects orders from your stores and marketplaces, ad spend and product costs, and calculates contribution margin for every SKU daily, including bundle and free-gift costs.