Order economics and acquisition limits
eCommerce Google Ads profitability starts with contribution.
Revenue-based ROAS does not show what is left after product costs, fulfilment, payment fees, shipping support and returns. Calculate contribution before ads, then derive an order-level advertising allowance.
Contribution first. Advertising allowance second.
Contribution before advertising
Revenue is one input to the decision.
Revenue-based ROAS is not a profit calculation.
When reported conversion value represents revenue, ROAS is attributed revenue divided by ad spend. Two products can show the same revenue ROAS and leave very different amounts available for acquisition.
Google Ads can use different conversion-value definitions. Confirm what your account reports before interpreting its value/cost ratio. A revenue target and a profit-based value model are not interchangeable.
Calculate contribution before advertising.
Contribution = revenue − COGS − payment fees − fulfilment − shipping subsidy − expected returns/refund allowance − other variable costs.
Use an order-level basis consistently. Exclude sales tax collected for a tax authority from money available to fund acquisition. Shipping subsidy means the cost you absorb after shipping revenue. Count refunds and incremental return handling once, without subtracting a refunded-revenue loss already removed from the revenue figure.
Translate contribution into advertising limits.
| Decision | Definition |
|---|---|
| Break-even CPA | Contribution before advertising; no contribution remains for overhead or profit at this point. |
| Break-even ROAS | Revenue divided by positive contribution before advertising. |
| Target CPA | Contribution minus the amount you want to keep after advertising. |
| Target ROAS | Revenue divided by a positive target CPA. |
A hypothetical €100 order.
€100 revenue minus €60 variable costs leaves €40 contribution. The break-even order CPA is €40 and break-even ROAS is 2.50×. Reserving €15 after ads leaves €25 target CPA, equivalent to 4.00× revenue ROAS.
This is arithmetic, not a recommended target or client outcome. It excludes fixed overhead unless the chosen post-ad contribution covers it. Calculate your own order economics.
Do not let averages hide the decision.
Product mix
Group products where different contribution, return or stock economics would change a budget or bid decision. A blended margin can conceal low-contribution bestsellers.
Discounts and returns
Review representative allowances against realised orders. Promotions, markdowns and return rates can make historical targets unhelpful.
New and repeat orders
Use a consistent new-customer definition. Lifetime-value assumptions need actual repeat behaviour, timing and cash-flow context.
Keep a practical weekly commercial view.
Review spend, comparable orders, platform-attributed revenue, store revenue, product mix and estimated contribution together. Label what is measured, estimated and missing.
If the assumptions are too weak to support a scale decision, the useful next action may be better data. A more precise-looking dashboard does not resolve uncertain inputs.
Need to decide what to fix first?
The €650 eCommerce Diagnostic reviews the wider account and turns the evidence into a prioritised roadmap and review call. Ongoing management is scoped around catalogue, markets and implementation needs.
Written by Andrei Visan.
I’ve worked hands-on with Google Ads since 2010. This resource explains a diagnostic approach, not a claim of specific client results.
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