ROAS and ROI are related, but they should not be used interchangeably.
ROAS measures revenue efficiency
ROAS divides attributed advertising revenue by media spend. It is fast, channel-friendly and useful for campaign optimization. It normally excludes product cost, people, software and creative production.
ROI measures return after cost
Marketing ROI subtracts the investment before dividing by that investment. The most decision-useful version starts from incremental contribution or profit, not gross revenue.
For example, $30,000 of revenue on $10,000 of cost is 3× ROAS. Under a simplified revenue-based ROI formula, the return is 200%. If the revenue carries $12,000 in product and fulfillment costs, the economic ROI is much lower.
Which one should lead?
Use ROAS for daily media diagnostics and ROI for investment decisions. Neither removes the need to examine incrementality, cash timing, customer quality and total acquisition cost.
Sources
This guide is educational and does not provide financial, accounting, tax or legal advice.