How to Set Target CPA and Target ROAS in Google Ads

Question 1

How do I calculate my first Target CPA from my Google Ads data?

Accepted Answer

The article recommends taking baseline CPA from an unconstrained Maximize Conversions period and setting the first Target CPA 10% to 20% above that baseline. If baseline CPA is $50, the article recommends an initial target between $55 and $60. Setting the target at or below current CPA forces conservative bidding that typically loses impression share and volume.

Question 2

How do I calculate my first Target ROAS from my Google Ads data?

Accepted Answer

According to groas, the first Target ROAS should be set 10% to 20% below baseline ROAS from a Maximize Conversion Value period. If baseline ROAS is 500%, the article recommends an initial target between 400% and 450%. The buffer gives the algorithm room to find conversions across more auctions before the constraint is tightened.

Question 3

How much conversion data do I need before switching to Target CPA or Target ROAS?

Accepted Answer

The article recommends aiming for at least 30 conversions before switching to a target-based strategy. It notes Google’s documentation suggests 15 conversions over 30 days as a minimum, but states 30 or more gives a far more reliable baseline. If an account converts fewer than 30 times per month at the campaign level, the article recommends using portfolio bid strategies that pool data across campaigns.

Question 4

When does Target CPA work better than Target ROAS?

Accepted Answer

According to groas, Target CPA works best when conversions have roughly equal value, such as lead generation where every lead is worth approximately the same amount. The article cites B2B SaaS demo requests and home services phone calls as classic use cases. It states Target CPA also tends to outperform in lower-volume accounts because it only needs to learn cost-per-conversion patterns.

Question 5

When should I use Target ROAS instead of Target CPA?

Accepted Answer

The article states Target ROAS is the better choice when conversions have meaningfully different values, such as a $30 order versus a $300 order in ecommerce. Using Target CPA there treats both equally and gravitates toward cheaper, lower-value conversions. For Target ROAS to work, the article requires passing accurate conversion values back to Google Ads, since wrong, static placeholder, or missing values will cause optimization toward bad data.

Question 6

How do I tighten Target CPA or raise Target ROAS without killing volume?

Accepted Answer

The article recommends tightening in increments of 10% to 15% maximum and waiting at least two full weeks between adjustments. If Target CPA is $55, it recommends lowering to $49 or $47, not $35; if Target ROAS is 400%, it recommends raising to 440% or 460%, not 600%. If volume drops more than 15% to 20% after a change, the article recommends reverting because the target was tightened too aggressively.