How the ROAS Calculator works
Return on ad spend (ROAS) measures how much revenue an advertising campaign, channel, or account generated relative to what it cost to run. It is the most common top-line metric marketers use to compare campaigns, and it uses one standard formula.
The formula
ROAS = Ad Revenue ÷ Ad Spend
Divide the revenue attributed to a campaign by the amount spent to run it. The result can be expressed as a ratio (a ROAS of 4.0, often written 4:1) or as a percentage (400%) — both say the same thing: every $1 of ad spend produced $4 of tracked revenue.
Break-even ROAS and gross margin
ROAS on its own does not tell you whether a campaign was profitable, because it ignores the cost of the goods or services sold. A campaign can post an impressive ROAS and still lose money if margins are thin. To find the minimum ROAS needed to cover the cost of goods sold, divide 1 by your gross profit margin (as a decimal):
Break-even ROAS = 1 ÷ Gross Margin
At a 50% gross margin, break-even ROAS is 1 ÷ 0.50 = 2.0. A ROAS above 2.0 starts contributing toward profit after the cost of goods sold; a ROAS below 2.0 means the campaign is losing money on that basis, even with positive revenue. At a 25% margin the break-even line rises to 4.0 — thinner margins require a stronger ROAS just to cover costs.
Estimating ad-attributed profit
Applying gross margin to revenue gives a rough profit estimate: multiply ad revenue by the gross margin to get gross profit, then subtract ad spend.
Ad-attributed profit = (Ad Revenue × Gross Margin) − Ad Spend
For example, $20,000 of ad revenue at a 50% gross margin and $5,000 of ad spend gives (20,000 × 0.50) − 5,000 = $5,000 of estimated profit, on top of a 4.0x ROAS. This figure ignores overhead, returns, and other fixed costs, so treat it as directional rather than a full profit-and-loss statement.
What ROAS does not capture
- Attribution window and model: platforms often credit a conversion to an ad if it happened within a set window (say, 7 days after a click). Changing the window or the attribution model (last-click, first-click, data-driven) changes reported revenue and therefore ROAS, without any change in actual performance.
- Blended vs. platform-reported ROAS: a single ad platform's dashboard often over-credits itself relative to a blended view built from total revenue and total ad spend across all channels. Compare consistently.
- Cost of goods sold and overhead: raw ROAS = Revenue / Spend ignores COGS entirely, which is why the break-even ROAS and profit figures above matter for a fuller picture.