Break-even ROAS is the revenue-to-ad-spend ratio at which the contribution from sales just covers advertising costs. In a simplified model, divide 1 by the contribution margin before advertising, expressed as a decimal.
This is a planning calculation. Its usefulness depends on including the relevant costs and using a revenue figure consistent with those costs.
Start with contribution margin
For this guide, contribution margin before ads means the share of revenue remaining after variable non-ad costs. Those might include the product, payment fees, packaging, and delivery costs paid by the seller.
Suppose a €100 order has €60 of those costs. It leaves €40 before advertising, so the contribution margin is 40%, or 0.40.
That €40 is the maximum ad spend per order that this simplified model can support before the contribution after advertising becomes zero.
The break-even ROAS formula
Break-even ROAS = 1 ÷ contribution margin before ads.
At a 40% margin, 1 ÷ 0.40 = 2.5× ROAS.
The same result appears at order level: €100 revenue ÷ €40 ad spend = 2.5.
| Contribution margin before ads | Simplified break-even ROAS |
|---|---|
| 20% | 5× |
| 25% | 4× |
| 40% | 2.5× |
| 50% | 2× |
| 60% | About 1.67× |
These are mathematical examples, not recommended targets or market benchmarks. A zero or negative margin cannot support positive ad spend under this model.
Why discounts can change the target sharply
Take the same product with €60 in variable non-ad costs. Reduce the selling price from €100 to €80 while those costs stay unchanged.
The contribution is now €20, or 25% of revenue. Break-even ROAS rises from 2.5× to 4×.
A higher conversion rate during the sale may help, but it does not remove the lower contribution per order. Recalculate the economics before using the old ROAS target for a promotion.
What the simple formula leaves out
Fixed overhead, one-off production costs, and a desired profit are not covered unless you explicitly account for them. Breaking even on contribution after ads does not mean the entire business has broken even.
For a fixed campaign cost, use a scenario with expected order volume and allocate that cost transparently. Avoid hiding a volume assumption inside a margin percentage.
Account for expected refunds and returns consistently. Use net revenue where appropriate and include costs that remain after a return.
Be careful with repeat-purchase value
Future purchases may improve customer economics, but they also bring future product and service costs. Do not substitute lifetime revenue for contribution without a clear time horizon and supporting evidence.
Keep an initial-order view alongside any longer-term model so the difference is visible.
Use the result in campaign planning
Compare your threshold with the campaign’s reported ROAS, then check attribution, revenue definitions, and cost completeness. Google’s ROI guidance provides related context on revenue and costs.
Use the ROAS calculator for the observed ratio and the ROAS versus ROI guide to explain why exceeding this threshold is only one part of a profitability decision.