Beginner’s Guide to Google Ad Testing

I was recently asked how to run ad tests on Google effectively. It’s a great question because ad testing is one of the most powerful tools for optimizing campaigns. Let’s face it — even with experience, you can’t always predict which copy will resonate best with your audience.

As I thought about it, I realized that ad testing isn’t a one-size-fits-all approach. The method you choose depends on what you’re trying to learn, your timeline, and how confident you want to be in the results.

In this post, I’ll explore three key approaches:

• Ad Variations
• Ad Group-Level Testing
• Campaign-Level Testing

Keep reading to find out which strategy will work best for your goals!

Ad Variations

As the name suggests, Ad Variations involve swapping out one piece of copy for another to see what resonates best with your audience. This method is perfect for testing granular edits—like tweaking your call-to-action (CTA)—on well-performing, mature ads to further refine their effectiveness.

I often use Ad Variations when I want to experiment with different CTAs to squeeze out incremental improvements without disrupting a proven ad. Since it’s relatively low risk, it’s ideal for making small, targeted changes while keeping the core message intact.

For more details, check out the official Google Ads documentation here.

Ad Group-Level Testing

Even with responsive search ads, testing is still essential. Within a single ad group, you can run up to three ad variations, allowing you to compare different approaches.

I use this method when I’m trying to figure out which language or tone connects best with the customer. In these cases, the bulk of the two ads will differ significantly. However, be mindful of ad rotation settings. While it might be tempting to run all ads evenly to collect data, in my experience, Google will naturally serve the best-performing ad more frequently. Optimizing for that top ad doesn’t mean your variations won’t get served—just be sure to monitor performance closely.

One tip: Track your ad variations using a label or URL parameter so you can easily see results and learn what works.

Custom Experiments

Custom Experiments are a powerful feature at the campaign level, offering flexibility for various types of tests, including creative testing. Essentially, this tool allows you to clone a campaign and set up a test variation, which could even include an entirely new set of ads.

I turn to this feature when testing brand-new concepts that are critical enough to require statistically significant results. It’s perfect for introducing fresh creative ideas, especially when you want to validate them before rolling them out across an entire account. By limiting the test to a small portion an account, you can document clear results or prevent a potentially harmful concept from affecting overall performance.

One of the most useful aspects of Custom Experiments is that you can set up expected outcomes—like a statistically significant lift in conversion rate—so Google monitors the results for you.

For more details on setting up a campaign-level experiment, check out the Google Ads documentation here.

Happy Testing!

The right test for you depends on the question you’re looking to answer. Now that you’re familiar with the different ways to run tests in Google Ads, you’re better equipped to make informed decisions that will optimize your campaigns.

If you need help setting up a test or want to discuss your strategy in more detail, feel free to reach out through the contact section.