Search themes in Performance Max: how they work and how to pick them

This guide is built from Google Ads Help: About search themes, About search themes in Performance Max campaigns, Use search themes with your Performance Max campaign and About ad group and asset group prioritization. The campaign type as a whole is covered in our Performance Max guide, and the other asset group signal in audience signals.

What search themes are

Performance Max uses what Google calls keywordless targeting: it works out which searches to show for from your assets, website and feeds. Search themes let you add to that. Google describes them as "words and phrases that describe what your customers are likely to search for", and says they help "especially for niche products, new offerings, or specific customer needs."

Google's own framing is useful: "Think of search themes as the unique knowledge you have about your business or product that AI can't easily know from your landing page, creative assets, or feeds." They are set per asset group, on the Signals card, next to audience signals.

Search themes are not only for Google Search. When Google launched them in October 2023, its announcement said they help reach that traffic "across all Google Ads inventory including Search, YouTube, Gmail, Discover, Maps, and Display".

What they are not

• Not keywords with match types. Google says search themes "provide a broader signal to Google's AI" than keywords. There are no brackets or quotes, and no keyword-level bids.
• Not a limit. Search themes "are optional and additive" to the searches Performance Max finds on its own. Asked whether they limit traffic, Google answers no.
• Not required. Google calls them "an optional input you can use to drive better performance."

If you want to restrict where Performance Max shows, search themes are the wrong tool; you need negative keywords, brand exclusions or URL rules, covered below.

When to add them

Google lists the cases where search themes help most:

• your landing page doesn't have complete or current details about what you offer;
• you've just expanded into a new market or launched a new product or service without much performance history;
• you're launching a seasonal promotion or sale;
• you want broader coverage on important business themes, including on Search;
• you want to help a campaign ramp up faster.

Google's example is a museum with a good outdoor space for children but no dedicated landing page for it. Adding "activities for children" and "outdoor recreation" as search themes tells Performance Max to look for those searches.

Limits and how to add them

• Up to 50 per asset group. At launch in 2023 the limit was 25; Google's current pages say 50.
• Up to 80 characters each.
• No duplicates. Google's example: avoid "car" and "automobile", "as they'll reach the same audience."
• Policy applies. Themes must follow the Google Ads Policies; ineligible ones show a policy error.

To add them: open the Performance Max campaign, go to Asset groups, switch to the Summary view, select the pencil icon next to Signals, choose Search themes, type each theme and press Enter (or paste a comma-separated list), then Save. You can remove themes at any time; Google notes that "Traffic derived from that search theme may stop serving."

Search themes and your Search campaign keywords

If you run Search campaigns next to Performance Max, Google's prioritization rules decide which one serves a search. Google says search themes "act as the equivalent to phrase or broad match keywords that are identical to the search query." The order is:

1. an exact match keyword identical to the search term;
2. phrase and broad match keywords (including AI Max) or search themes identical to the search term;
3. the most relevant ad group or asset group, chosen by AI;
4. the highest Ad Rank.

Google's example: for the search "skydiving license", an exact keyword [skydiving license] in a Search campaign wins over everything; without it, a search theme "skydiving license" wins over the phrase keyword "skydiving", because the theme is identical to the search and the keyword isn't. "Identical" includes spelling corrections but not plurals or synonyms.

One consequence: Performance Max asset groups with no search themes are "selected based on the highest Ad Rank" against your other ads, and the same applies to keywordless AI Max ad groups and Dynamic Search Ads. So if a search matters to you, an exact match keyword in a Search campaign is the way to keep it there. How the match types work is in our guides to keyword match types and broad match.

Negative keywords and brand exclusions

"Exclusions and negative keywords still apply" to search themes, Google says, and "Search themes respect brand exclusions rules." In practice:

• Negative keywords can be added to a Performance Max campaign or at account level, and apply to Search and Shopping inventory only. Google recommends using them "only for essential brand safety needs or to block completely irrelevant terms", warning they can stop the AI finding valuable traffic. Our search terms and negative keywords guide covers how they match.
• Brand exclusions stop Performance Max showing on searches for a brand, including misspellings and subsidiary brands, on Search and Shopping. Google recommends them over negative keywords for keeping your own brand searches in a separate campaign. See our brand exclusions guide.

Can you use competitor names as search themes? Google says "Yes, competitor brands and keywords can work as search themes, but you're responsible for complying with local laws and regulations."

Where the clicks land

Search themes don't have their own landing pages. Google's launch post says results from search themes go to the pages set by Final URL expansion, page feeds and URL contains rules. If your site has pages you don't want ads to land on, set those controls first. Google's controls combinations page calls Final URL expansion plus search themes "the foundational setup for Performance Max", and suggests adding URL exclusions for blog, policy or support pages.

Seeing what they bring in

Google suggests two ways to measure search themes:

• Before and after: "compare campaign-level performance before and after adding search themes."
• Search terms insights: under Insights, search terms are grouped into categories with clicks, conversions and conversion value, and you can see which asset groups each category appeared in. Google's search terms insights page covers it.

Performance Max now also has its own search terms report: in the Search terms report, choose "Search terms and landing pages for Performance Max" to see individual search terms with their landing pages and ad formats, from March 2023 on.

How to pick good search themes

Google's best practices:

• Add new information. If your page covers "custom t-shirts", Google suggests "event apparel printing" as a theme if the site doesn't already feature that niche.
• Avoid duplicates and close variants.
• Go broad. Use "running shoes" rather than "red running shoes size 10".
• Be specific for events, such as "Christmas decorations" or "back to school supplies".

How we use search themes

This is our own practice, not Google's guidance:

• We write themes per asset group, matched to that group's products or services and landing pages, rather than one long list copied everywhere.
• We start with the services or products a client sells that the website doesn't describe well, then fix the website too.
• Searches the client must control (brand, top services) stay as exact match keywords in a Search campaign.
• We review the Performance Max search terms report monthly and add negatives only for clearly irrelevant terms.

If you want help setting up or reviewing Performance Max, see our services.

Frequently asked questions

How many search themes can I add in Performance Max?

Up to 50 per asset group, each up to 80 characters. The limit was 25 when search themes launched in 2023.

Are search themes the same as keywords?

No. They are a broader signal with no match types. For prioritization against Search campaigns, Google treats them like phrase or broad match keywords.

Will a search theme beat my exact match keyword?

No. An exact match keyword identical to the search term is prioritized over search themes and other keywords.

Do search themes limit where Performance Max shows?

No. They are additive. To restrict searches, use negative keywords or brand exclusions.

Where can I see results from search themes?

In search terms insights and the Performance Max search terms report, and by comparing campaign performance before and after adding them.

For more on Google Ads targeting, see our guides to AI Max for Search and account structure.