How to Calculate ROAS
The standard ROAS formula is simple: divide attributed revenue by advertising spend. The interpretation becomes more useful when you separate new-customer revenue, repeat revenue, refunds and gross margin.
Example calculation
If you spend $10,000 and attribute $35,000 in revenue, reported ROAS is 3.5. In practice, document your assumptions and compare the reported number with the business outcome you can verify. Measurement is most useful when the team understands what the data includes, what it misses and which decision the metric is meant to support.
Choose the revenue window
Decide whether you are measuring immediate purchase revenue or a longer customer value window. In practice, document your assumptions and compare the reported number with the business outcome you can verify. Measurement is most useful when the team understands what the data includes, what it misses and which decision the metric is meant to support.
Subtract refunds when appropriate
Gross sales can overstate performance when refund rates vary by campaign. In practice, document your assumptions and compare the reported number with the business outcome you can verify. Measurement is most useful when the team understands what the data includes, what it misses and which decision the metric is meant to support.
Compare consistently
Use the same model and time window when comparing campaigns. In practice, document your assumptions and compare the reported number with the business outcome you can verify. Measurement is most useful when the team understands what the data includes, what it misses and which decision the metric is meant to support.
Add contribution margin
A contribution-margin view can tell you whether the campaign actually produces cash, not merely revenue. In practice, document your assumptions and compare the reported number with the business outcome you can verify. Measurement is most useful when the team understands what the data includes, what it misses and which decision the metric is meant to support.
What to do next
Choose the next guide based on the decision you are trying to make. If your main problem is collection quality, start with server-side tracking. If the data exists but channels disagree, study attribution models. If you are evaluating software, compare implementation, integrations and decision value—not marketing claims alone.