The short answer
Revenue efficiency is not the same as profit
ROAS uses attributed revenue in the numerator and advertising spend in the denominator. It can be calculated before product cost, fulfilment, fees, salaries, tax, and other costs are considered.
ROI is broader and profit-based. Google Ads describes ROI as a ratio of net profit to costs and notes that the exact method depends on the campaign goal. That is why an ROI percentage is incomplete unless the page states what it counted as profit and which costs it treated as the investment.
Side-by-side
ROAS and ROI comparison
| Question | ROAS | ROI |
|---|---|---|
| Primary job | Measure attributed revenue efficiency of media spend. | Measure profit relative to a defined investment. |
| Typical numerator | Revenue or conversion value attributed to ads. | Profit after the costs included in the model. |
| Typical denominator | Ad spend. | The investment cost defined by the calculation. |
| Output | Multiple or percentage, such as 4.00× or 400%. | Percentage, such as 50%. |
| Main limitation | Does not subtract non-media costs. | Changes when the cost or profit boundary changes. |
| Best use | Campaign or channel efficiency under one consistent attribution setup. | Profitability analysis with a clearly stated cost boundary. |
Illustrative arithmetic
The same campaign can show a high ROAS and a smaller contribution return
- Attributed revenue
- $8,000
- Ad spend
- $2,000
- Contribution margin before ads
- 45%
This is an arithmetic illustration, not a benchmark, forecast, net-profit statement, or total-business ROI calculation. Fixed and unentered costs are excluded.
Choosing the metric
Use the label that matches the question
Use ROAS for attributed media efficiency
Keep the reporting period, conversion event, currency, attribution window, and attribution model consistent. A platform's attributed revenue is not automatically the same as incremental revenue caused by the campaign.
Use a profit-based measure for cost-aware decisions
List the costs in the numerator and denominator. If only variable costs and ad spend are included, label the result as contribution-based rather than total business ROI.
Primary sources
Definitions used on this page
- Google Ads glossary — defines ROAS as total conversion value divided by total spend and ROI as total profit divided by total spend.
- Google Ads: About return on investment — explains ROI as a net-profit-to-cost ratio and shows that the exact method depends on the goal.
- Google Ads platform-comparable conversion methodology — documents attribution and view-through differences that can affect reported conversion value and ROAS.
Sources reviewed September 1, 2026. See the full calculator methodology for formula and model limitations.