The essentials
- Conditions: at least 30 conversions a month, reliable conversions with values, and a search campaign already in place; without those, Performance Max has nothing to learn from.
- Minimum budget: €1,000 to €1,500 a month for six weeks to get out of the learning phase; below that, the results cannot be interpreted.
- Exclusions: brand terms, otherwise the campaign captures your own awareness and reports a flattering ROAS.
- How to read it: the results are read in GA4 or the CRM, excluding brand, and compared with the search campaign over the same period.
Performance Max has become the default Google Ads campaign for e-commerce and a frequent complement in lead generation. How it works in general is described in Performance Max: definition ; this article deals with the concrete case of a small business, where the volume of data is limited and where a poorly configured campaign eats a budget without producing readable results.
The conditions to meet before launching
| Condition | Threshold | If it is missing |
|---|---|---|
| Conversion volume | 30 a month minimum on the account | Stay on search alone, with optimised CPC |
| Reliability of conversions | No duplicate conversions, values filled in | Fix measurement before any automation |
| Existing search campaign | Structured, with three months of history | Start with that; Performance Max does not replace search |
| Content available | 15 headlines, 5 descriptions, images in 3 formats, 1 video | Google generates mediocre content in your place |
| Product feed (e-commerce) | Titles, images, prices and stock up to date | Erratic delivery, ineligible products |
| Budget | €1,000 to €1,500 a month for 6 weeks | A learning phase that never ends |
The setup step by step
- Choose the objective: sales with values for a retailer, leads for a service business, with a single primary conversion. Optimising on three different conversions dilutes the learning.
- Set the bidding: start on “maximise conversions” with no target for two weeks, then move to target CPA or ROAS at the level observed, never at the level wanted; the mechanism is explained in Smart Bidding.
- Structure the asset groups: one group per family of offers or products, with its own copy and visuals. A single campaign for the whole catalogue makes any reading impossible.
- Fill in the audience signals: customer list, converted visitors, search themes matching your commercial queries. They speed up learning without restricting delivery.
- Add the extensions: sitelinks, callouts, prices, phone number, as on search; see Google Ads ad extensions.
- Set the exclusions: brand terms, unsuitable placements, areas outside your commercial territory; the method is in negative keywords.
- Wait: six weeks with no change greater than 20% to the budget or the target.
The exclusions that change everything
Without excluding brand terms, Performance Max captures searches on the company name, which you would have got for free organically. The reported ROAS rises, real customer acquisition stays invisible, and the budget shifts towards an audience you already have. Two methods: request the exclusion of brand keywords at account level, or keep a separate brand search campaign that captures those queries first. This precaution is the first to take and the most often left out; it is among the most frequent Google Ads mistakes.
Reading the results without getting it wrong
| Metric | Where to read it | What to check |
|---|---|---|
| Cost per conversion or ROAS | GA4 or the CRM, not Google Ads | The gap with the Google Ads figure measures the overstatement |
| Brand share | Search terms report | Above 30%, the campaign is living off your awareness |
| Share of new customers | Segment in Google Ads or the CRM | An acquisition campaign must bring in new customers |
| Split by channel | Reports by channel (since 2025) | Delivery heavily weighted to display signals targeting that is too broad |
| Cannibalisation | Change in search over the same period | A rise in PMax with an equivalent fall in search brings nothing |
The account's reference metrics are covered in detail in the Google Ads KPIs.
When to give up
Three situations justify not using Performance Max. An account with fewer than thirty monthly conversions does not provide enough signal, and the campaign spends without converging. A complex B2B sale with no conversion value leads the algorithm to optimise towards the cheapest form, often off target; a search campaign managed on cost per qualified lead is then a better option. Finally, an advertiser who needs to control their search terms, for regulatory or competitive reasons, will not get that level of control. In those cases a well-structured search campaign remains more profitable, as explained in structuring a Google Ads account.
How GreenRed helps
Rather than juggling several tools, GreenRed's Google Ads module brings these metrics together in a single dashboard, compares them over time and tells you which actions come first. You can try it free, with no card, from the Pricing.
Frequently asked questions
Should a small business use Performance Max?
Yes, if the account generates at least thirty reliable conversions a month, has a structured search campaign and can commit €1,000 to €1,500 a month for six weeks. Below those thresholds the campaign has nothing to learn from and a well-run search campaign remains more profitable.
What is the minimum budget for Performance Max?
From €1,000 to €1,500 a month for at least six weeks, the time needed to get out of the learning phase. A smaller budget produces results that cannot be interpreted, and any change of more than 20% to the budget or the target restarts that phase.
Should brand terms be excluded?
Yes, systematically. Without exclusions, Performance Max captures searches on the company name, which you would have got for free, which inflates the reported ROAS and hides real acquisition performance. You exclude at account level or keep a separate brand campaign.
Does Performance Max cannibalise the other campaigns?
It takes priority over standard Shopping campaigns and can take traffic from search on the same queries. The check is to compare the account's total conversions before and after the launch, not the performance of the new campaign alone.