How to calculate ROAS and what it does not show.
ROAS is the return on ad spend: the revenue generated by the campaigns divided by the amount invested in them. A ROAS of 4 means R$ 4 in revenue for every R$ 1 in media. The math is simple. What takes care is knowing which number is good for your margin.
Fabrício MartinsFounder of Martin Marketing & Design
In short
- Formula: ad revenue divided by ad spend.
- ROAS is not ROI: ROAS looks only at media and revenue. ROI considers all costs and the profit.
- Minimum ROAS: 1 divided by your margin. With a 25% margin, the break-even point is 4.
- What is left out: repeat purchases, sales closed off the website and costs beyond media.
The ROAS formula
ROAS = revenue generated by ads ÷ ad spendThe result is a multiplier. It can also be shown as a percentage: a ROAS of 4 is the same as 400%.
The acronym stands for return on ad spend. To calculate it, you need two numbers from the same period: how much you invested in media and how much revenue came from the campaigns.
The first number is in the platforms’ dashboards. The second depends on measurement: sales need to be tied to the ads that generated them, through conversions set up on the website or a record of the sales closed by the sales team.
A step-by-step example
A service company invests R$ 3,000 a month in ads. The average cost per click is R$ 2.50, so the campaign generates 1,200 visits. Of those, 4% become leads: 48 people. Sales closes 25% of the leads, which makes 12 sales. With an average sale value of R$ 1,200, revenue is R$ 14,400.
R$ 14,400 ÷ R$ 3,000 = ROAS 4.8
Notice that four variables went into the math besides the budget: cost per click, page conversion, close rate and sale value. Improving any one of them improves ROAS. You can test these numbers in the simulator on our page about paid media management.
ROAS vs. ROI: they are not the same thing
| ROAS | ROI | |
|---|---|---|
| What it measures | Revenue per real invested in media | Profit on the whole investment |
| Costs considered | Only the ad budget | Media, product, team, tools and management |
| What it is for | Comparing campaigns and channels | Knowing whether the business is making money |
| Can mislead when | The margin is low | Costs are poorly allocated |
It is possible to have a high ROAS and a loss. If the company sells at a 15% margin and the campaign has a ROAS of 5, every R$ 1 invested generates R$ 5 in revenue, but only R$ 0.75 in margin. The campaign loses money, even though the dashboard shows a pretty number.
What is a good ROAS? It depends on the margin
There is no universal number. What exists is the break-even point: the ROAS from which the campaign stops losing money.
Break-even ROAS = 1 ÷ contribution margin
| Margin | Break-even ROAS | Reading |
|---|---|---|
| 50% | 2.0 | Above 2, the campaign pays for itself |
| 40% | 2.5 | Below that, each sale costs more than it brings in |
| 25% | 4.0 | A tight margin demands a very efficient campaign |
| 20% | 5.0 | Hard to sustain on paid media alone |
That is why a good paid media manager’s first question is not how much you want to invest. It is what your margin is. The ROAS goal comes from it.
How to find your contribution margin
The break-even formula depends on a number many companies do not have at their fingertips: the contribution margin. It shows how much is left of each sale after the costs that only exist because the sale happened.
Contribution margin = (price − variable costs) ÷ price
Variable costs include:
- The cost of the product or of the hours to deliver the service.
- Sales taxes.
- Card and platform fees.
- Shipping and packaging, when you pay for them.
- Sales commission.
An example: a product sold at R$ 200 has R$ 70 in cost, R$ 20 in taxes, R$ 10 in fees and R$ 20 in shipping. Variable costs add up to R$ 120. That leaves R$ 80, a 40% margin. This company’s break-even point is a ROAS of 2.5.
Rent, fixed salaries and tools do not go into this math. They are paid with what is left after media, and that is why operating exactly at break-even still means a loss at the end of the month.
From break-even to goal: how to set the target ROAS
The break-even point says where the campaign stops losing. The goal needs to sit above it, and you can calculate by how much.
Decide what share of revenue you want left over after paying variable costs and media. That remainder is what will cover fixed costs and profit.
Target ROAS = 1 ÷ (margin − desired remainder)
In the example company, with a 40% margin: if it wants 15% of revenue left over, it can spend up to 25% of what it sells on media. The target ROAS is 1 ÷ 0.25, that is, 4.
| Margin | Desired remainder | Maximum ad spend as a share of revenue | Target ROAS |
|---|---|---|---|
| 40% | 10% | 30% | 3.3 |
| 40% | 15% | 25% | 4.0 |
| 40% | 20% | 20% | 5.0 |
Notice the effect: each extra point of remainder demands a much more efficient campaign. That is why the ROAS goal is a business decision, not a media decision. It comes from a conversation between whoever handles finance and whoever handles the ads.
What ROAS does not show
- Repeat purchases. ROAS looks at the first sale. If the customer buys again, the real return is higher. Businesses with recurring revenue can accept a lower initial ROAS.
- Sales off the website. Leads that close by phone or WhatsApp do not appear in the dashboard if nobody keeps track.
- Attribution. The person saw an ad on Meta, searched on Google and bought. Which channel got the credit? Each platform tends to claim it for itself.
- Costs beyond media. Creative production, tools and management do not go into the math.
None of this makes ROAS useless. It only means it should be read together with other numbers, such as cost per sale and customer value over time.
The math changes when the customer comes back
Traditional ROAS looks at one sale. In businesses with repeat purchases, that underestimates the return.
Imagine a pet supplies store. A new customer’s first purchase is R$ 150, and winning them cost R$ 60 in ads. The ROAS of the first sale is 2.5. With a 40% margin, that is exactly the break-even point: the store neither gains nor loses.
Except that this customer buys again every two months. In a year, that is six purchases and R$ 900 in revenue for the same R$ 60 in media. The real return on that investment is 15.
To do this math, track three numbers: the average purchase value, how many times the customer buys per year and how long they remain a customer. With them, you decide with confidence how much you can pay for the first sale. Without them, it is easy to pause exactly the campaigns that bring the best customers.
How to improve ROAS
- Fix the landing page. Doubling the page’s conversion doubles ROAS without spending one more real on media.
- Cut what does not convert. Keywords, audiences and placements that only eat up budget.
- Refresh the creative. A tired ad costs more and converts less.
- Raise the order value. Combos, bundles and complementary offers lift revenue per sale.
- Use remarketing. People who have already visited the website convert at a lower cost.
- Check the measurement. A duplicated or missing conversion distorts the number and leads to wrong decisions.
If you are still choosing the channel, see the comparison between Google Ads and Meta Ads.
ROAS in services: when the sale happens off the website
In service companies, the ad does not generate a sale. It generates a lead. The sale happens later, by phone, on WhatsApp or in a meeting. In that case, more useful than tracking ROAS every day is knowing the maximum cost you can pay per lead.
Maximum cost per lead = sale value × margin × close rate
With a sale value of R$ 1,200, a 50% margin and a 25% close rate, each lead is worth, on average, R$ 150 in margin. That is the ceiling: paying more than that per lead means a loss. To have money left over, the goal needs to sit well below it.
In the example at the start of this article, the campaign generated 48 leads with R$ 3,000, a cost of R$ 62.50 each. It is within the ceiling, with room to spare.
This math only works with a simple sales record: which campaign each lead came from, and which ones closed. Without it, the platform optimizes to generate cheap leads, which are not always the ones who buy.
Overall ROAS, by channel and by campaign
The same calculation can be done at three levels, and each one answers a different question.
- Overall. All ad revenue divided by the whole budget. It answers: does the media investment pay for itself?
- By channel. Google on one side, Meta on the other. It answers: where to put the next real?
- By campaign or ad. It answers: what to pause and what to scale?
Looking only at the overall number hides problems. An overall ROAS of 4 can be the average between one campaign at 8 and another at 1. Separating the levels shows where the money is well invested and where the waste is.
How often to track it
Tracking it every day creates anxiety and rushed decisions, because the numbers fluctuate. Tracking it only at the end of the month is too late to correct course.
A rhythm that works: look at ROAS by campaign once a week, for adjustments, and close the overall number once a month, comparing it with the break-even point. Businesses with a long sales cycle need a wider window, because the revenue from an ad can show up weeks after the click.
It is worth recording these numbers in a simple spreadsheet, month by month. Before long, you see the seasonality of your market and stop mistaking for a problem what is just the normal behavior of each time of year.
Common mistakes when reading ROAS
- Adding up the dashboards. If Google and Meta claim the same sale, the sum of the two shows more revenue than the company actually billed. Always check against the real sales number.
- Comparing different windows. Each platform counts the conversion within a period after the click or the view. Different periods produce numbers that cannot be compared.
- Mixing brand search with the rest. Whoever searches for your company name was already going to buy. Brand campaigns have a very high ROAS and inflate the average.
- Ignoring cancellations and returns. The platform records the sale at the moment of purchase and does not deduct what was returned.
- Counting shipping as revenue. If the conversion value includes shipping and taxes, ROAS looks better than it is.
- Deciding with too little data. A campaign with three sales does not have a ROAS. It has a coincidence.
Frequently asked questions
CPA is the cost per acquisition: how much you paid for each sale or lead. ROAS relates that cost to revenue. Two ads with the same CPA can have different ROAS if they sell products of different values.
Almost always, but there are exceptions. Acquisition campaigns in businesses with strong repeat purchases can run at a loss on the first sale, as long as the customer’s value over time makes up for it. This is a decision that needs data, not hope.
Record the source of each lead the moment it arrives, in a CRM or a spreadsheet, and mark which ones became sales and for how much. With that, you add up revenue by campaign and do the math outside the platform.
It is a good trend indicator, not a bank statement. The dashboard only sees the sales it can track and tends to credit itself with what other channels helped build. Use it to compare campaigns with each other and confirm the overall result with the company’s sales numbers.
There is no number that fits every store. A store with a 50% margin profits at a ROAS of 3. Another, with a 20% margin, loses money at the same number. The ideal ROAS is the one that sits above your break-even point, with room to cover fixed costs.
Conclusion
Calculating ROAS takes a minute. Interpreting it requires knowing the margin, measuring sales for real and remembering what is left out of the math.
Define the break-even point before investing and track the number every week. If you want someone doing this for you, with full access to the accounts, get to know Martin’s paid media management.
