Break-even ROAS is 1 divided by your contribution margin. If you keep 40 cents of every euro of revenue after variable costs, your break-even ROAS is 2.5: every euro you spend on ads must return €2.50 in revenue just to cover itself. Anything below that loses money on the first sale, no matter how good the dashboard looks.
Most small business owners we talk to know their ROAS (return on ad spend) because the platform shows it in bright numbers. Far fewer know the ROAS at which their ads stop being a cost and start being profit. Without that number, you cannot judge a campaign, set a bidding target or have a sensible conversation with an agency. This guide gives you the formula, three worked examples and the costs people most often forget.
What is ROAS, and what does it leave out?
ROAS is conversion revenue divided by ad spend. If you spend €1,000 and the platform reports €4,000 in sales, ROAS is 4.0, often written as 400%.
The number is useful, but it measures revenue, not profit. It does not know about:
- the cost of the goods you sold,
- shipping, packaging and payment processing fees,
- refunds and returns,
- VAT, if your platform revenue is reported gross,
- discount codes that reduced what you actually collected.
That is why a 4.0 ROAS can lose money in one business and a 2.0 can be very profitable in another. The difference is margin.
How do you calculate break-even ROAS?
Use this formula:
Break-even ROAS = 1 ÷ contribution margin
Contribution margin is the share of each sale left after all variable costs, expressed as a decimal. Variable costs are those that rise with each order: product cost, shipping, payment fees, returns allowance and so on. Fixed costs such as rent or salaries are not included here.
To calculate the margin, take one typical order:
- Write down the revenue you actually collect, excluding VAT.
- Subtract product cost, shipping, packaging, payment fees and an allowance for returns.
- Divide what is left by the revenue. That is your contribution margin.
Worked example: an online shop
An illustrative store sells a product for €80 excluding VAT. Product cost is €28, shipping and packaging €7, payment fees €2.50 and a returns allowance €2.50. That leaves €40 of contribution, a 50% margin.
Break-even ROAS is 1 ÷ 0.50 = 2.0. At a ROAS of 2.0, the ads pay for themselves and nothing more. At 3.0, each €1,000 of spend returns €3,000 in revenue and €500 in profit after costs (€1,500 contribution minus €1,000 ad spend).
Worked example: a lower-margin retailer
Another illustrative shop sells a €50 item with a 25% contribution margin. Break-even ROAS is 1 ÷ 0.25 = 4.0. A campaign showing ROAS 3.5 looks healthy in the dashboard and loses €0.125 on every euro spent. That shop would need to improve margin, raise prices or accept the campaign as customer acquisition, not profit.
What target ROAS should you actually set?
Break-even is the floor, not the goal. Your target needs to cover things the formula excludes:
- the agency or freelancer fee,
- creative and landing page costs,
- a share of fixed overheads,
- a profit you are actually happy with.
A practical rule we use: start with break-even, then add a cushion that reflects how much profit you want from the first order. For a business that expects strong repeat purchases, a break-even first order can be perfectly fine, because the customer’s later orders are the profit. For a one-purchase product, you need profit on the first sale or the model does not work.
| Margin | Break-even ROAS | Sensible target (first order must profit) |
|---|---|---|
| 20% | 5.0 | 6.0 or higher |
| 30% | 3.3 | 4.0 or higher |
| 40% | 2.5 | 3.0 or higher |
| 50% | 2.0 | 2.5 or higher |
| 60% | 1.7 | 2.0 or higher |
The target column is our rule of thumb for illustration, not a universal benchmark. Your own numbers decide it. If you are using automated bidding, be careful about feeding a target into the algorithm that you have not worked out yourself. We explain the risks in our piece on target ROAS bidding on a small budget.
What if you sell services or generate leads?
ROAS is awkward for lead generation, because the revenue arrives weeks later and from a fraction of the leads. The equivalent is break-even cost per lead:
Break-even CPL = average profit per customer × close rate
Say a service business earns €1,200 contribution from a typical new customer and closes 1 in 5 qualified leads (20%). Break-even cost per lead is €1,200 × 0.20 = €240. Spending more than €240 per lead loses money; at €120 per lead you are making roughly €120 per lead on average.
If you do not know your close rate, measure it for a month before judging any campaign. Ads that produce cheap leads that never answer the phone are worse than ads producing expensive leads that buy. Our landing page and ad alignment audit helps when the problem sits between the click and the enquiry.
Why does platform ROAS often disagree with your accounts?
Three common reasons:
- Attribution windows. Platforms count a sale if the customer clicked, or even just viewed, an ad within a window. Some of those customers would have bought anyway.
- Overlap between platforms. Google and Meta can both claim the same order, so adding up platform revenue can exceed your real revenue.
- Revenue definitions. Platforms may report gross revenue including VAT or before returns.
The fix is to compare platform numbers with your shop’s or CRM’s actual revenue for the same period. Divide total new-customer revenue by total ad spend across all platforms and call it your blended ROAS. We go deeper on this in why your Facebook ROAS is lying to you.
What about repeat customers and lifetime value?
If customers come back, first-order break-even may be too strict. Suppose an illustrative shop has a 40% margin, so first-order break-even ROAS is 2.5, but the average customer places 2.2 orders over a year. You could accept a first-order ROAS of about 1.5 to 2.0 and still earn a profit over twelve months, provided the repeat rate is real and measured, not hoped for.
The danger is optimism. Use a repeat rate you have observed in your own data over a fixed period, and apply it conservatively. If you have fewer than a few hundred customers, treat your lifetime figures as rough. A good compromise is to run two numbers side by side: first-order break-even as the red line you watch weekly, and twelve-month break-even as the strategic target you review quarterly.
Which mistakes make break-even ROAS wrong?
- Using gross margin from the price list. It ignores shipping, fees and returns, which can easily remove another 10 to 15 points of margin.
- Forgetting discounts. If a third of orders use a 10% code, your average revenue per order is lower than the list price.
- Mixing VAT into revenue. Strip it out before dividing, or your break-even looks lower than it is.
- Never updating it. Supplier prices, shipping rates and platform fees change. Review the number every quarter.
A five-minute ROAS check you can do today
- Pick one best-selling product or service and write down its true variable costs.
- Calculate contribution margin and break-even ROAS (or break-even CPL).
- Pull last month’s actual revenue and total ad spend from your own books.
- Compare blended ROAS with break-even. Above it, you are profitable on the first sale; below it, your repeat purchases must carry the model.
- Write the break-even number on the first page of your reporting, so every future decision starts there.
The bottom line
A ROAS figure is only meaningful next to the margin behind it. Work out your break-even ROAS once, update it when costs change, and judge every campaign and every agency report against it. It turns a vanity metric into a decision tool, and it takes about the same time as a coffee break.