How to Calculate ROAS (Return on Ad Spend) — and Why It's Not the Same as Profit

ROAS is the ratio of revenue generated from advertising to the cost of that advertising. A ROAS of 4 means you generated $4 in revenue for every $1 spent on ads. The formula: Revenue from ads / Ad spend.

What ROAS tells you

ROAS tells you how efficiently your ad spend is generating top-line revenue. It's the most commonly used metric in advertising because it's simple to calculate and directly connects spend to revenue. Platform-reported ROAS (what Google or Meta tells you) is based on the conversions the platform can observe and attribute. Your actual ROAS may differ based on your own attribution model and whether you're counting all revenue or only revenue the platform can see.

What ROAS doesn't tell you

ROAS doesn't tell you whether you're profitable. Revenue isn't profit. If your product costs $50 to produce and deliver, and you spend $25 on ads to sell it for $100, your ROAS is 4 ($100 / $25). Your profit margin after ad spend is ($100 - $50 - $25) / $100 = 25%. The ROAS looks healthy. The profitability depends on your margins.

ROAS also doesn't capture the lifetime value of acquired customers. A customer who costs $50 to acquire and makes a $30 first purchase has a terrible ROAS on that transaction — 0.6. If that customer goes on to spend $500 over three years, the initial ROAS was misleading. Measuring ROAS on first purchase alone undervalues acquisition advertising for any business with meaningful repeat purchase behavior.

Target ROAS by business model

The ROAS you need depends on your margins:

High-margin businesses (software, digital products, 70-90% margins) can sustain lower ROAS because each sale is highly profitable. A ROAS of 1.5-2 might be profitable.
Medium-margin businesses (ecommerce physical products, 40-60% margins) typically need ROAS of 2-4 to be profitable after all costs.
Low-margin businesses (retail, consumer goods, 20-30% margins) need higher ROAS — often 4-8+ — to turn a profit after ad costs.

ROAS vs. ROI

ROI (Return on Investment) is broader than ROAS. ROI accounts for all costs — not just ad spend, but also the cost of goods sold, shipping, overhead, salaries, agency fees, and any other expense associated with producing and delivering what you sell. ROI = (Revenue - Total Costs) / Total Costs.

ROAS is a component of ROI, not a substitute. A campaign with strong ROAS can still generate negative ROI if the non-advertising costs consume the revenue the ads generated. The most common advertising mistake: optimizing for ROAS while margin slowly erodes because nobody is looking at the full P&L.