Glossary
What is ad rotation in Google Ads?
Melvin Salas1 min readVerified 7 October 2026
Short answer
Ad rotation is a Google Ads setting that, in Google's words, allows you to specify how often you'd like the ads in your ad group to be served relative to one another. Google says you can use it in Shopping, Search and Display campaigns, and that there are 2 settings: 'Optimise' and 'Do not optimise'.
Google says the 'Optimise' setting optimises your ads for clicks in each individual auction using signals, and prioritises ads that are expected to perform better than other ads within an ad group. As data is accumulated, ad serving will become weighted more heavily in favour of the ads that look statistically likely to perform better.
It also says serving can stay level. Google says it's possible for ad serving to remain relatively even within this setting, for example if ads in an ad group have similar performance, or if the ad group doesn't receive a significant amount of impressions and clicks for some period of time.
If you're using Smart Bidding, Google says Google Ads will automatically use the 'Optimise' ad rotation setting. Google says 'Do not optimise' delivers your ads more evenly into the ad auction for an indefinite amount of time, that it isn't recommended for most advertisers, and that even then the percentage of impressions for each ad may not be even due to the quality of the ad.
Our reading, not Google's: on a small account the setting is rarely the decision. Under Smart Bidding it is made for you, and what is worth reading is the result, each ad's share of the ad group's impressions, alongside how long the ad group has been running.
Reading these columns is daily work for us
Riibon watches every campaign daily and holds a baseline for each metric, so a move in impression share or Quality Score is judged against what is normal for that account, not against a rule of thumb, before anyone acts on it.
Ask the Riibon app whether your campaigns are losing to budget or to rank. It is free, with no time limit and no card. Or book a call and we run it for you.