Google Ads keeps improving Performance Max (PMax) so that advertisers can reach potential customers more efficiently. One useful feature, search themes, gives you more control over search. It is especially suitable for accounts that are new to PMax, lack conversion data, or want to strengthen search performance.
Below is a quick guide to what search themes are, how to use them, and how they help your campaigns reach their goals faster.
1. What are PMax search themes?
Search themes are a supporting setting in Google Ads PMax campaigns. They let you provide topic terms related to your products or services (not traditional keywords), helping Google understand your business and conversion goals more accurately.
With search themes, PMax campaigns can capture users interested in you more effectively on the Search Network, reaching high-intent traffic even if you are not running keyword ads.
2. How are search themes different from keywords?
Keywords in traditional Search campaigns are about one-to-one matching with search terms, whereas search themes give Google’s system a hint about direction.
Google does not trigger ads directly from these themes. Instead, they supplement the learning signals and help the system better understand what potential converters might search for. So they don’t replace keywords; they help the system appear more intelligently in the right searches.
| Comparison | Search campaigns: keywords | PMax: search themes |
|---|---|---|
| Core purpose | Match search terms precisely | Give the system a directional hint and strengthen learning signals |
| How it works | Triggered when the user’s search term matches a keyword you set | The system uses the theme to judge whether to show an ad; triggering is not guaranteed |
| Where it is used | Search campaigns | Performance Max campaigns |
| Control | High: advertisers can adjust bids and match types manually | Low: left to Google’s automatic optimisation |
3. Three benefits of adding search themes
1. Wider search coverage and more chances to reach potential customers
Traditionally, PMax relies on the account’s conversion history, audience signals and page content to learn and decide where to serve. But if the account is new or lacks data, its reach on the Search Network may be limited.
With search themes, PMax can take part in auctions on Google search results pages more actively. Even if your account is not yet running keyword ads, it can capture search queries related to your products or services, increasing brand exposure and conversion opportunities.
Example: you are an e-commerce brand selling outdoor camping gear. After entering search themes such as “hiking tents” and “camping lights”, PMax may still show your ads when users search for these terms, even though you did not set them as keywords.
2. Faster learning and optimisation, with a shorter warm-up period
For new accounts without much conversion data, or newly created PMax campaigns, the system can lack a clear direction early in the learning phase, which lengthens learning and makes performance unstable.
Search themes can fill this data gap, helping the system understand early on which queries and audiences are most likely to convert, so it moves into optimisation faster and overall ad efficiency improves.
Especially suitable for:
- New brands or new products in their launch phase
- Accounts that have not yet integrated GA4 or first-party data
- Accounts with too few target conversions that keep re-entering the learning phase
3. Better system understanding and prediction for stronger overall performance
PMax works from multiple signals (such as ad assets, audience lists and conversion behaviour), and search themes become an important reference for the system to judge user intent.
When search themes work together with other assets (such as images, headlines and descriptions), they help Google build a more complete semantic network and intent prediction model, making it easier for your ads to appear in front of the right people at the right time.
4. How to set up PMax search themes
It takes just three steps:
- Create a PMax campaign in Google Ads
- Find the “Search themes” section (next to the audience signal settings)
- Enter up to 25 theme terms related to your products or services
Tip: use simple, general theme terms, such as “outdoor gear”, “business translation” or “affordable luxury travel bags”, and avoid terms that are too niche or obscure.
5. Frequently asked questions
Q1: Will search themes conflict with my keyword campaigns?
A: No. Search themes are a supporting signal specific to PMax. They don’t affect the settings in your existing keyword campaigns and won’t take their impressions.
Q2: Will entering a search theme always trigger ads?
A: Not necessarily. Search themes only give the system a reference direction. Whether an ad is triggered is still decided automatically by the system based on your conversion goals and learning data.
Q3: How many themes can I enter? Are there format restrictions?
A: You can enter up to 25 theme suggestions. Use simple, general terms (such as “hiking gear” or “translation company”) and avoid terms that are too niche or overly specialised.
Q4: What mistakes should I avoid?
A: Avoid entering terms with the same meaning (such as “car” and “automobile”), as this can cause overlapping resources and confuse the system’s learning, so it cannot optimise effectively.
Q5: Can I enter competitors’ names?
A: Where laws and policies allow, you can use competitor brand or product names as search themes to help you reach potential customers who are comparing options. But check that this does not breach Google Ads policies or industry rules.
Q6: In which situations are search themes a good fit?
Search themes are especially useful in the following situations, helping to make up for the early learning phase or a lack of data:
- Entering a new market or launching a new product or service
- Your web content is incomplete or lacks detailed descriptions
- Your ad account has little data and no past performance record
- You are about to launch a holiday season promotion or price cut and need to expand search reach quickly
