ROAS measures revenue; ROI measures profit
ROAS (return on ad spend) measures how much revenue is generated for every dollar spent on advertising, expressed as a ratio or a percentage. ROI (return on investment) typically nets out the cost of goods sold and other costs first, to arrive at actual profit relative to the investment made. A campaign can show a healthy ROAS while still being unprofitable overall if the business's margins are thin — which is why ROAS is best interpreted alongside gross margin, not as a standalone profitability signal.
ROAS, worked
ROAS is calculated by dividing revenue by ad spend. With $42,000 in revenue against $10,000 in ad spend, ROAS is $42,000 ÷ $10,000 = 4.2, commonly written as 4.2:1 or 420%. Profit from ad spend alone is revenue minus ad spend: $42,000 − $10,000 = $32,000 — this figure does not subtract the cost of goods, fulfillment, or other business costs, so it isn't the same as overall profit.
- ROAS (ratio) = revenue ÷ ad spend → $42,000 ÷ $10,000 = 4.2
- ROAS (percentage) = (revenue ÷ ad spend) × 100 → 420%
- Profit (from ad spend alone) = revenue − ad spend → $42,000 − $10,000 = $32,000
The 4:1 'good ROAS' benchmark — and its limits
A 4:1 ROAS is a commonly cited benchmark for a good return on ad spend across many digital-marketing contexts, while 1:1 marks the point at which ad spend is exactly recovered in revenue, before any other cost is considered. But the ROAS actually needed for overall profitability depends heavily on gross margin: lower-margin businesses need a higher ROAS than higher-margin businesses to be profitable once product and fulfillment costs are factored in. A ROAS above 1:1 is not automatically a profitable campaign once those other costs are included.
Breaking the funnel down: CPM, CPC, CTR, CVR, CPA
ROAS and ROI describe the outcome, but diagnosing why a campaign underperforms usually requires looking at the funnel stage by stage. With $2,000 in spend, 400,000 impressions, 6,000 clicks, and 180 conversions: CPM (cost per 1,000 impressions) is ($2,000 ÷ 400,000) × 1,000 = $5; CPC (cost per click) is $2,000 ÷ 6,000 ≈ $0.33; CTR (click-through rate) is (6,000 ÷ 400,000) × 100 = 1.5%; CVR (conversion rate) is (180 ÷ 6,000) × 100 = 3%; and CPA (cost per acquisition) is $2,000 ÷ 180 ≈ $11.11.
A change in CPA can originate from any upstream stage — CPM, CTR, or CVR — so reviewing all five together, rather than CPA (or ROAS) alone, is what actually shows whether a campaign's performance changed because of weaker ad relevance, a weaker landing page, or more expensive inventory.
When ROAS and ROI diverge
Because ROAS uses gross revenue and ignores the cost of goods, fulfillment, and other operating costs, two campaigns with identical ROAS can have very different actual profitability if their underlying margins differ. Applying a single generic ROAS target, like 4:1, without adjusting for a business's own gross margin is one of the more common ways teams misread ad performance — the number that determines real profitability is ROI, not ROAS, even though ROAS is the more commonly reported figure on ad platforms.
よくある質問
How is ROAS calculated?
Divide revenue generated by an advertising campaign by the amount spent on that campaign. A ROAS of 4:1 means $4 in revenue was generated for every $1 spent on ads — $42,000 in revenue against $10,000 in spend gives a ROAS of 4.2.
What is the difference between ROAS and ROI?
ROAS divides revenue by ad spend and doesn't account for the cost of goods or other business costs, while ROI typically nets those costs out first to measure actual profit against the investment made. A campaign can have a healthy ROAS while still being unprofitable on an ROI basis if margins are thin.
Does a ROAS above 1:1 mean the campaign was profitable?
Not necessarily overall. A ROAS above 1:1 means revenue exceeded ad spend, but it doesn't account for the cost of goods, fulfillment, or other operating costs that still apply to that revenue. Overall profitability depends on whether gross margin on that revenue covers ad spend plus all other associated costs.
What is a good ROAS?
A ROAS of 4:1 is a commonly cited general benchmark for a strong return on ad spend, but the ROAS actually needed for overall profitability depends on the business's gross margin — lower-margin businesses need a higher ROAS than higher-margin businesses to be profitable once product and fulfillment costs are considered.
How do CPM, CPC, CTR, and CVR relate to ROAS?
CPM, CPC, CTR, and CVR measure cost and conversion efficiency at each stage of the funnel — impressions, clicks, and conversions — while ROAS measures the revenue outcome relative to spend. A campaign can have efficient funnel metrics but still show weak ROAS if the average revenue per conversion is low, so the two sets of metrics are typically reviewed together.
参考文献
- Google Ads Help. Understanding ROAS, CPM, CPC, and conversion metrics. support.google.com/google-ads.
- Interactive Advertising Bureau (IAB) and Media Rating Council (MRC). Digital advertising measurement guidelines. iab.com; mediaratingcouncil.org.
- Kotler P, Keller KL. Marketing Management. 15th ed. Pearson, 2016.