Contribution margin is the money a sale contributes after paying for everything that came with it. Subtract the variable costs of one order from what the customer paid, and the rest is what you have to spend on ads, salaries, rent and profit. It is the foundation of break-even ROAS, maximum CPA and POAS.
What goes into it
Variable costs are the ones that rise and fall with each order:
- Product cost, or COGS
- Packaging and inserts
- Shipping and courier charges
- Payment gateway fees, including cash-on-delivery charges
- An allowance for returns, refunds and refused deliveries
- Marketplace or platform transaction fees, if any
Fixed costs such as salaries, rent and software subscriptions are left out. They are paid from the total contribution of all orders.
Contribution margin before and after ads
Some teams use two levels, and it helps to name them clearly:
| Level | Formula | Use |
|---|---|---|
| Contribution margin (before marketing) | Price − variable costs | Break-even ROAS and maximum CPA |
| Contribution after marketing | Price − variable costs − ad cost per order | Whether each order actually made money |
Worked example
Example: a $50 order.
| Line | Amount |
|---|---|
| Selling price | $50.00 |
| Product cost | $18.00 |
| Packaging | $1.50 |
| Shipping | $6.00 |
| Payment fees | $1.80 |
| Returns allowance | $2.20 |
| Contribution margin | $20.50 (41%) |
- Break-even ROAS = 50 ÷ 20.50 ≈ 2.4
- Maximum CPA = $20.50
- At a $14 CPA, contribution after marketing is $6.50 per order
Why it matters for Meta ads
Contribution margin tells you how much Meta is allowed to cost. Without it, a ROAS target is a guess. With it, you can set a ROAS goal or cost per result goal that reflects your real economics, and you can see which products deserve budget. The break-even ROAS calculator works out contribution margin, break-even ROAS and maximum CPA together.
How to improve it
- Raise average order value with bundles, so shipping and packaging are spread across more revenue.
- Renegotiate courier rates as volume grows.
- Reduce returns with clearer sizing, photos and descriptions.
- Encourage prepaid orders where cash on delivery has high refusal rates.
- Be careful with discounts. They cut the price while costs stay the same.
For the full method, read how to calculate break-even ROAS.
Frequently asked questions
How do you calculate contribution margin per order?
Take the price the customer paid and subtract every cost that comes with that order: product, packaging, shipping, payment fees and an allowance for returns. A $50 order with $29.50 of variable costs has a contribution margin of $20.50, or 41%.
What is the difference between contribution margin and gross margin?
Gross margin usually subtracts only cost of goods sold from revenue. Contribution margin also subtracts the other variable costs of each order, such as shipping, fees and returns. For ad decisions, contribution margin is more accurate.
Does contribution margin include ad spend?
Usually not. Contribution margin before marketing is the budget available to pay for ads, which is why break-even ROAS is price divided by it. Some teams also track contribution after marketing, which subtracts ad cost per order.
What is a good contribution margin for e-commerce?
It varies widely by category. Higher margins give ads more room, so a brand with a 60% contribution margin breaks even at a ROAS of about 1.7, while one at 25% needs 4.0. Calculate your own rather than borrowing a benchmark.
