ROAS: definition, formula and break-even point

What is ROAS?

Each platform phrases it its own way. The Google Ads Help page on Target ROAS describes “the average conversion value (for example, revenue)” you’d like to get “for each dollar you spend on ads”. In the interface, the actual ratio appears in the “Conv. value/cost” column of the “Conversions” columns list. Multiply it by 100 to get a percentage.

Meta talks about “Purchase ROAS”. According to its help pages, the metric divides purchase conversion value by amount spent. Google Analytics 4, for its part, offers a “Return on non-Google ad spend” metric. It is only populated if you import your cost data.

It is a gross return: revenue per euro of advertising, without the margin or the company’s other costs.

How do you calculate ROAS?

Calculating ROAS means dividing conversion value by the ad spend for the same period.

ROAS = conversion value excluding tax ÷ ad spend

Example (calculation): a campaign costs €10,000 over a month and generates €40,000 of attributed revenue excluding tax. Its ROAS is 40,000 ÷ 10,000 = 4. Multiplied by 100, it reads 400%.

The same result takes several forms depending on the tool.

What value goes in the numerator?

Conversion value must exclude tax and shipping, with no duplicates and no refunded purchases. Otherwise, the ratio shown overstates the return.

For the GA4 purchase event, the Google for Developers documentation asks you to set value to the sum of price × quantity of the items: “Don’t include shipping or tax”. The transaction_id parameter prevents the same purchase from being counted twice. The GA4 non-Google return metric also subtracts refunds.

The value can also be a margin. Google Ads states that conversion value can be sales revenue “or profit margins”. It can vary from one conversion to the next (dynamic values) or stay the same for all of them (static values). Checking conversions is the first step of a Google Ads audit.

What spend goes in the denominator?

The denominator is the amount spent on the ad platform, the one Google Ads or Meta displays. Agency fees, ad creation and tools are left out: they count in ROI. Compare two ratios only if they cover the same scope of costs and the same period.

What ROAS should you aim for? Calculating your break-even point

The right ROAS is the one above your break-even point. That point depends on your margin: break-even ROAS = 1 ÷ margin.

Let m be the contribution margin before advertising, as a share of revenue excluding tax. A sale bringing in revenue R leaves m × R to pay for advertising. Break-even is reached when m × R equals the spend, so R ÷ spend = 1 ÷ m.

1. Start from the selling price excluding tax of an average order.
2. Subtract the purchase or production cost, the shipping you pay, payment fees and commissions.
3. Divide what is left by the price excluding tax: you get the contribution margin m.
4. Calculate 1 ÷ m: this is the minimum ratio for advertising not to lose money.
5. Compare this break-even point with the ratio measured on value excluding tax, over the same period.

Fictitious example (calculation): an order of €100 excluding tax costs €50 to buy, €8 to ship and €2 in payment fees. €40 is left, a 40% margin and a break-even point of 2.5 (250%).

This table applies the formula 1 ÷ margin. Its values are calculation results, not market benchmarks.

The break-even point reasons on a single order. If your customers buy again, also reason on customer lifetime value (LTV): later purchases can make up for a first order with little profit.

ROAS, ROI, CPA: what is the difference?

ROAS measures the revenue produced per euro of advertising. ROI measures the profit after costs. CPA measures the cost of one conversion.

Example (calculation): €10,000 of spend and €40,000 of revenue excluding tax give a ROAS of 4. With a 40% margin, sales generate €16,000, so €6,000 of profit and an ROI of 60%. With a 25% margin, the same campaign earns nothing.

The metric is also linked to CPA: ROAS = average order value ÷ CPA. An average order value of €80 excluding tax obtained for a CPA of €20 gives 4. CAC (customer acquisition cost) follows the same logic, at the level of the customer rather than the order. CPA, conversion value and other acronyms are defined in our SEA lexicon.

Why is a platform’s ROAS not your real ROAS?

The figure shown by Google Ads, Meta or GA4 is an attributed ROAS: it counts the conversions the platform links to its ads, according to its own rules. Three rules set it apart from the revenue in your back office.

The attribution model. Google Ads no longer supports the linear, time decay, first click and position-based models (Google Ads Help on attribution models). Last click and data-driven remain, data-driven being the default for most conversion actions. Choosing an attribution model is explained in our web analytics guide.

The conversion window. By default, Google Ads tracks conversions for 30 days; a conversion that happens after the chosen window is not recorded. The last few days are therefore incomplete: Google advises excluding the most recent conversion delay period from the evaluation.

Modelling. When events are missing, Meta may use statistical modelling. On devices running iOS 14 and later, its Purchase ROAS may not be calculated.

Each ad platform applies these rules to its own ads. The same sale can therefore be claimed by both Google Ads and Meta, and the total of sales attributed by the platforms can exceed your real sales.

Attributed ROAS or incremental ROAS?

An attributed ROAS observes that a sale followed an ad. It does not prove that the sale would not have happened without it. Incrementality, on the other hand, establishes cause and effect for a campaign or a channel.

Google has lowered the entry cost of these tests. According to a Google Ads Help post of November 11, 2025, a test that could cost more than €100,000 can now be done for €5,000. Google presents three complementary measurements: incrementality (cause and effect), marketing mix models or MMM (the overall view) and attribution (how credit is shared).

How do you set a target ROAS in Google Ads and Meta?

Start from your break-even point and your history. Google recommends setting the target “based on your business goals as well as your historical ROAS performance as a reference”.

Google advises recording conversion values for four weeks, or one to two conversion cycles, before setting the target. Meta’s ROAS goal aims for an average weekly ratio close to the target; the other ad platforms are covered in our social ads guide.

Google’s 15 conversions give access to the strategy, but they are not enough to judge its results: how Smart Bidding strategies work, Target ROAS included, is detailed on our dedicated page. In Performance Max campaigns, the target is optional.

Since June 2026, “Maximize conversion value with a Target ROAS” has been called “Target ROAS”, with no change in behaviour. Since August 17, 2026, Google has changed its bidding for budget-limited campaigns using Target CPA or Target ROAS, with possible temporary fluctuations.

How do you improve ROAS without skewing the measurement?

Improving ROAS starts with making what it counts reliable: a ratio inflated by a value including VAT or by duplicates has gained nothing.

1. Make the value reliable: excluding tax and shipping, deduplicated by transaction_id, refunds deducted.
2. Send the margin rather than revenue when you can. With cart data and the cost of goods sold (COGS) from the Merchant Center feed, Google Ads calculates gross profit metrics. The Merchant Center feed is presented in our guide to Shopping campaigns.
3. Meet the bidding requirements: Google recommends at least 15 conversions per month, frequent uploads (ideally daily), enhanced conversions and data-driven attribution (Google Ads best practices).
4. Exclude the most recent days from each review, until late conversions come in.
5. Improve the landing page’s conversion rate: it increases the value obtained per euro spent.
6. Test before rolling out: one variable at a time, with the platform’s reading period (at least 7 days at Meta).