How ROAS is calculated
Divide attributed revenue by ad spend. A campaign with $4,000 in revenue and $1,000 in advertising costs has 4× ROAS, or 400%. This means four dollars of attributed revenue per dollar of advertising spend; it does not mean three dollars of profit. Google Ads presents a comparable conversion-value-per-cost metric as conversion value divided by cost.
Estimate a missing total
If spend is unavailable, multiply cost per click by clicks. If revenue is unavailable, multiply clicks by conversion rate, then by average order value. Both estimates depend on accurate inputs and attribution. If you enter direct totals, they take precedence over optional estimates. Keep a record of which method you used before comparing campaigns.
ROAS is not ROI
A campaign can have a ROAS above 1× and still lose money after the cost of the product or service and other expenses. A useful target depends on your contribution margin and business goals. Review customer acquisition cost, repeat purchases, and incremental impact rather than declaring a universal good ROAS for every industry.