Performance Max: how a PMax campaign works and when it's worth using
Performance Max (PMax) is a Google Ads campaign type that serves ads across Search, Google Shopping, YouTube, Gmail, Discover, and the Display Network from a single place. For e-commerce stores, it is often the most important campaign in the account today. Here is how it works and how to set it up so it does not burn through your budget.
How Performance Max works
Instead of manually selecting keywords and placements, you provide Google with assets (text, images, video, product feed), a conversion goal, and audience signals. The algorithm itself decides who, where, and at what cost to show the ad to achieve the result.
When PMax makes sense
You have a store with a feed in Google Merchant Center.
The account properly tracks conversions along with order values.
The budget allows you to gather at least several dozen conversions per month per campaign.
With very small budgets or a lack of sales data, it is better to start with Search and standard Shopping campaigns.
Asset groups and audience signals
It is worth dividing asset groups by product category or margin rather than throwing the entire store into one group. Add signals to each group: customer lists, store visitors, and search terms your customers use. Signals do not restrict targeting, but they help the algorithm find the right people faster.
Most common problems with PMax
Brand cannibalization. PMax eagerly captures searches for your brand name that would have converted anyway. Exclude brand terms at the account level and run a separate brand campaign.
Poor assets. The lack of video causes Google to generate them automatically, usually with poor quality.
No product segmentation. Bestsellers eat up the entire budget, while the rest of the catalog gets no chance.
Optimizing for conversion count instead of value. In e-commerce, target ROAS usually works better.
How to measure results
Check the channel reports and search terms reports to see where the budget is going. Also, compare PMax results with the overall store's MER. If PMax is growing but total sales are not, the campaign is likely taking credit for purchases from other sources. Read more about this in the article on what ROAS and MER are.
Summary
Performance Max can scale store sales very well, but only when given good data, strong assets, and a sensible structure. This is how we build accounts as part of our Google Ads management. Also, check how much advertising in Google Ads costs.
