Introduction
Ad rotation is a setting in Google Ads that determines how your ads are shown when you have multiple ads in the same ad group. If you’ve written several versions of ads to test different messaging or calls to action, ad rotation decides how often each version appears in auctions. This setting plays a key role in A/B testing, optimizing performance, and managing user experience.
How Ad Rotation Works
When you create multiple ads within a single ad group, Google Ads needs to decide which one to show each time your ad is eligible. The ad rotation setting instructs Google on whether to prioritize the best-performing ad or to distribute impressions more evenly.
Types of Ad Rotation Settings
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Optimize (default setting)
Google uses machine learning to prioritize ads that are more likely to perform better based on past click-through rates, conversion rates, device, browser, location, and other signals. Over time, better-performing ads get more impressions. -
Do Not Optimize: Rotate Ads Indefinitely
This option gives equal preference to all ads in the ad group, showing them more evenly over time. It’s most useful for advertisers who want to run controlled A/B tests or have specific compliance requirements where each ad must be shown equally.
When to Use “Optimize”
– You want Google’s algorithm to automatically prioritize high-performing ads
– You’re focused on conversions or CTR
– You have many responsive search ads or dynamic ads
– You don’t want to manually monitor ad performance
When to Use “Rotate Indefinitely”
– You’re conducting strict A/B testing to compare ad variations
– You need consistent impression distribution for reporting or legal compliance
– You want full manual control over optimization decisions
– You’re running experiments where you want fair exposure for each ad
Example:
Let’s say Zara is testing two ads for a summer dress collection:
– Ad A: “Shop Zara Summer Dresses – Lightweight & Trendy”
– Ad B: “Zara Summer Styles – New Arrivals in Store Now”
If “Optimize” is selected, and Ad A gets more clicks over time, Google will start favoring Ad A more in auctions. If “Rotate Indefinitely” is selected, both ads will be shown roughly equally regardless of performance.
Best Practices
– Start with “Rotate Indefinitely” when A/B testing to ensure fair comparison
– Switch to “Optimize” after identifying top performers to maximize conversions
– Always monitor CTR, conversions, and ROAS of each ad
– Don’t test too many ads at once—2 to 3 per ad group is ideal for meaningful results
– Use Responsive Search Ads in combination with ad rotation for better automation and scale
Conclusion
Ad rotation settings give advertisers control over how Google distributes impressions across multiple ads. “Optimize” leverages Google’s AI to maximize performance, while “Rotate Indefinitely” gives you full control for testing or compliance. By choosing the right setting based on your goals, you can improve ad relevance, boost campaign results, and run more effective experiments in your account.
