Contribution margin, not ROAS: the metric that should run your brand

ROAS is the most over-trusted number in DTC. It is easy to pull, easy to optimise, and it routinely points brands toward decisions that lose money. The metric that should run your brand is contribution margin.

What contribution margin is

Contribution margin is the money a sale leaves behind after the variable costs of making that sale, product cost, shipping, payment fees, fulfilment, and the marketing it took to acquire it. It is what is left to cover fixed costs and profit.

In plain terms: revenue minus everything that scales with each order. If that number is negative, you are paying customers to buy from you, no matter how good the ROAS looked.

Why ROAS misleads

• ROAS ignores product and fulfilment costs entirely, a 4× ROAS on a low-margin SKU can still lose money.
• It is reported per platform, each claiming the same conversion, so blended reality is worse than any dashboard.
• It rewards discounting, which inflates revenue while quietly eroding the margin that matters.

How to calculate it

1. 01Start with net revenue for the order (after discounts and returns).
2. 02Subtract product cost (COGS).
3. 03Subtract shipping and fulfilment.
4. 04Subtract payment processing fees.
5. 05Subtract the acquisition cost attributed to that order (blended, not platform-claimed).
6. 06What remains is contribution margin, in currency and as a percentage of net revenue.

“ROAS tells you a channel looked good. Contribution margin tells you the business made money.”

Running decisions on margin

Once decisions are scored on contribution margin, the right moves get obvious: scale the ad sets that are margin-positive at the blended level, kill the discounts that buy revenue at a loss, and prioritise products that actually contribute. This is why Atlas scores every decision on true margin, not platform ROAS.