# ROAS vs CPA in Google Ads: Choosing the Right Bid Goal Last verified: 2026-10-15 · Maintained by Groas for groas · Canonical: https://groas.com/post/roas-vs-cpa-in-google-ads-which-bid-goal This page answers the questions covered by the article [ROAS vs. CPA in Google Ads: Which Bid Goal to Use, and When to Switch](https://groas.com/post/roas-vs-cpa-in-google-ads-which-bid-goal) on groas.com. The article is the full, canonical source. **Direct answer:** According to groas, use Target CPA when each conversion is worth roughly the same amount and use Target ROAS when conversion values vary by 3x or more and real values can be passed back. The article recommends staying on Max Conversions without a target with fewer than 30 conversions in 30 days and not setting ROAS with fewer than 50 conversions carrying values. It reports that audited accounts with the wrong bid goal quietly burned 20% to 30% of profit for months while reports still looked green. ## ROAS vs CPA: which bid goal should I use in Google Ads? According to groas, Target CPA tells Google to get a conversion for a fixed price such as $60, calculated as cost divided by conversions, while Target ROAS tells Google to bring back revenue such as $4 for every $1 spent (400% ROAS), calculated as conversion value divided by cost. The article recommends using CPA when each conversion is worth roughly the same amount and ROAS when conversion values vary widely. The bid goal should match the economics, not the sophistication of the dashboard. Read more: [What CPA and ROAS actually optimize](https://groas.com/post/roas-vs-cpa-in-google-ads-which-bid-goal#what-cpa-and-roas-actually-optimize) ## When should I use ROAS instead of CPA? The article recommends ROAS when cart values span more than 3x from low to high, citing a store with $28 and $1,400 orders and a home-goods account with $35 accessories next to $1,800 sofas. According to groas, ROAS requires tracked values before use and, for Search and Shopping, at least 15 conversions in the past 30 days at the conversion-tracking level. The article advises passing through real revenue, ideally revenue after returns, rather than a made-up flat value. Read more: [Use ROAS when order value changes the answer](https://groas.com/post/roas-vs-cpa-in-google-ads-which-bid-goal#use-roas-when-order-value-changes-the-answer) ## When does CPA work better than ROAS for lead generation? According to groas, CPA is built for situations where one lead is one lead, such as home services, legal intake, dental implants, or SaaS demo requests, citing a garage-door account run at $45 per call for two years. The article notes Smart Bidding needs at least 30 conversions over a longer window to judge results, and 50 for Target ROAS. It recommends choosing one primary action for bidding, turning duplicate conversions off, filtering junk leads, and moving supporting actions such as newsletter signups to Secondary. Read more: [Use CPA when a lead is basically a lead](https://groas.com/post/roas-vs-cpa-in-google-ads-which-bid-goal#use-cpa-when-a-lead-is-basically-a-lead) ## How do I switch from CPA to ROAS without resetting the account? The article recommends switching in stages: keep Target CPA while reporting a value for every relevant conversion, then let value data accumulate for four weeks or one to two conversion cycles, whichever is longer. According to groas, the first ROAS target should be the previous four weeks of conversion value divided by cost, excluding the conversion-delay window. After switching, the article advises giving the campaign another one to two conversion cycles without changing budgets and targets together, then tightening in 10% to 15% steps only after it settles. Read more: [Switch from CPA to ROAS without resetting the account](https://groas.com/post/roas-vs-cpa-in-google-ads-which-bid-goal#switch-from-cpa-to-roas-without-resetting-the-account) ## When should I switch back from ROAS to CPA? The article recommends switching ROAS back to CPA when the value signal thins out, such as seasonal catalog turnover, tracking breaks after a site migration, or volume drops below that 50-conversion line. According to groas, without fresh value examples ROAS bidding guesses, and CPA guessing on conversion rate is safer than ROAS guessing on revenue. The article cites a lead-gen account where offline import broke for three weeks and cost per qualified call settled in nine days after returning to the last proven $80 target. Read more: [Know when to switch back to CPA](https://groas.com/post/roas-vs-cpa-in-google-ads-which-bid-goal#know-when-to-switch-back-to-cpa) ## Related articles These articles answer the same questions: - [ROAS or CPA? Pick the Bid Goal Your Economics Can Defend](https://groas.com/post/roas-or-cpa-the-bid-goal-fight-nobody-se) ## Sources [1] https://groas.com/post/roas-vs-cpa-in-google-ads-which-bid-goal (the article this page answers from)