Performance Max (PMax) is a Google Ads campaign type that runs a single campaign across all of Google’s advertising space (Search, Shopping, YouTube, Display, Discover, Gmail and Maps) and uses Google’s automation to decide where, when and to whom each ad is shown, in pursuit of the conversion goals you set.
How Performance Max works
You supply the ingredients and Google does the assembling. The main inputs are:
- Goals and bidding: the conversions that count, plus a bid strategy that aims for the most conversions or the most conversion value, optionally with a target cost per acquisition or return on ad spend. Bidding is always automated through Smart Bidding.
- Asset groups: headlines, descriptions, images, logos, videos and a final URL. Google combines them into ads that fit each placement.
- Audience signals: customer lists, website visitors and interests that give the system a starting point. They are hints, not limits.
- A product feed from Google Merchant Center for retailers, which powers Shopping ads.
- Search themes, locations and languages Which shape where the campaign can appear.
Performance Max began as a closed box. Google has since added controls and reporting, many of them during 2025. At the time of writing (October 2026) these include campaign-level negative keywords, brand exclusions, account-level placement exclusions, URL exclusions and the option to turn off final URL expansion, plus a search terms report, asset reporting and channel reporting. Check what your own account shows, as features reach accounts at different times.
Performance Max can compete with your search campaigns for the same searches. When a search is identical to one of your search campaign keywords, the search campaign normally takes priority. Otherwise, whichever has the stronger ad rank wins.
Why it matters
For UK online shops, Performance Max is now the main way to run Shopping ads with automation, having replaced Smart Shopping campaigns in 2022. With a clean product feed, good images and accurate conversion values, it can find sales across channels a retailer would struggle to manage one by one.
For lead generation the picture is mixed. A solicitor, clinic or trades business can get a flood of cheap form fills from Display and app placements that never turn into clients, because the system only knows a form was submitted. Feeding back which leads became customers, through offline conversion imports or enhanced conversions for leads, makes a large difference to what it learns.
It also needs data. With a small budget and few conversions per month, the system has little to learn from, and results can swing from week to week.
Common mistakes
- Launching before conversion tracking is checked, so the campaign optimises towards the wrong actions.
- Counting brand searches as new business. Performance Max picks up people searching for your name cheaply, which flatters the return.
- Uploading a few weak images and no video, then leaving Google to fill the gaps.
- Putting every product or service into one asset group, so the ads and landing pages are too general.
- Making big changes every few days during the first weeks, which can restart the bid strategy’s learning period each time.
- Judging lead generation campaigns on lead count rather than on how many leads became customers.
How to act on it
Before launch, check tracking, set conversion values that reflect what each action is worth, tidy the product feed and add brand exclusions if you run a separate brand campaign. Build asset groups around real product categories or services, each with its own landing page and its own images and video.
After launch, give it time to settle, then review monthly: channel reporting, search terms, placements and asset performance. If you already run Shopping or search campaigns, compare Performance Max against them in a controlled test rather than replacing them outright. Setting up and running these campaigns is the focus of my Performance Max management service.