Performance Max Search Themes: How to Guide Google’s AI

Performance Max search themes let you tell Google’s AI what your customers are looking for. You add words or phrases describing their needs. A search theme is a broader signal, not a keyword, and entering a phrase does not guarantee that your ad will appear for that query.

Start with customer needs that your website leaves unclear, then add those themes to the relevant asset group’s signals. You are providing business context, rather than an approved list of searches. For the bigger picture, read the Performance Max guide. Here, the task is to choose useful hints and understand their limits.

What does a search theme add?

Performance Max already predicts queries and placements using your assets, feeds, and landing pages. Search themes are optional additions to those predictions. They can supply context about a niche offering, a new service, or a particular customer need that your campaign materials do not explain.

In my work with service businesses, I find themes useful when the website barely describes the services. I use the customer’s wording. Imagine a cleaning company whose page says “property care,” while its customer asks for “move-out cleaning.” Let’s use this example to decide which themes to keep.

How many themes should you add, and which are useful?

According to Google, you can enter up to 50 distinct themes per asset group. That is a limit, not a target. Google recommends avoiding duplicates and close variants. A longer list of synonyms does not necessarily explain more about your customers.

Ask your specialist which customer need each theme describes and what context the website lacks. The table illustrates this review. Only consider a row if you provide that service and your website leaves the need unclear, then check for overlap with existing themes.

For each theme you keep, ask your specialist to show what context is missing from the service page. Broad wording avoids unnecessary attributes; a seasonal theme adds the occasion that prompts someone to buy. You can name that occasion without listing every detail. Google’s guidance on choosing search themes recommends both approaches.

Where do you add search themes?

The setting belongs to an asset group. If you are unsure which group to edit, first read the guide to Performance Max asset groups. Then follow Google’s instructions for adding search themes:

1. Open the Campaigns menu and go to Asset groups.
2. Switch to the Summary view.
3. Find the relevant asset group card and click the pencil beside Signals.
4. Select Search themes. Enter your chosen phrases, pressing Enter after each theme.
5. Click Save.

Before saving, read the list as a business owner. Do you actually provide the service described? Would a customer recognize their problem in those words? Could you explain why the phrase belongs there? These are checks on your meaning, not extra interface requirements.

What if the same phrase is a Search campaign keyword?

Under Google’s prioritization rules, an exact match keyword has the highest priority when it is identical to the search query. A search theme has the same priority as phrase match and broad match keywords only when the theme itself is identical to the query. “Identical” includes spelling corrections, but not synonyms or changes between singular and plural forms.

If no keyword or theme is identical to the query, Google selects based on the relevance of the query, keywords, and landing pages. Ad relevance and campaign settings also affect which ad is selected. Priority therefore does not guarantee an impression.

For the cleaning example, compare the query “move-out cleaning” with your exact match keyword and search theme. If both contain that same phrase, the keyword takes priority. A theme reading “end of tenancy cleaning” is not identical to that query, even though it describes the same service. Check the actual wording alongside the keyword’s match type.

When this does not apply

You need guaranteed visibility for a chosen query. A search theme cannot promise that. It also does not restrict Performance Max to the phrases you have entered.

You want to bypass a restriction. Negative keywords and exclusions still apply. Adding a theme does not cancel them.

You are filling space with similar phrases. Using the whole allowance is not evidence of a useful list. If the next theme repeats an existing idea, revisit the customer need instead of adding another wording variation.

Questions and answers

Can I leave search themes empty?

Yes. They are optional. Performance Max also predicts relevant queries and placements using your assets, feeds, and landing pages.

Should I copy my entire keyword list?

Avoid copying it wholesale. Select phrases that add context and remove close variants. Search themes do not replace Search campaign keywords.

Can I use themes for seasonal services?

Yes. Google recommends specific themes for seasonal events. Choose an occasion that genuinely relates to your offer, rather than adding a holiday simply because it is popular.

For your next account check, compare each theme with the service page it supplements, then check the negative keywords and exclusions that still apply. Use that review as a starting point for finding other places your Google Ads budget may be going to waste.