Choosing the size of your AdSense ad depends on the maximum available ad space and where exactly you want to place it on your site. When you create ads, Google by default shows recommended lists of ads for higher revenue generation. You can preview those ads and the mobile icon shown indicates the compatibility with mobile devices. Google measures the performance of your AdSense account and indicates the improvement under “Scorecard” section on your account dashboard and use of recommended ads is one of the criteria of AdSense scorecard. Though the scorecard does not have any direct impact on your account it is an indication of how effectively you follow the guidelines.
You can choose one of the recommended ads or click on the dropdown to choose your desired ad unit. Following are the broader categories of ad units and each category will have ad units of specified sizes.
- Recommended – showing by default
- Horizontal banner
- Vertical banner
- Custom size
- Link ads
Examples of ad placement is shown below covering different types of ad sizes on a page.
Though there is no certain rule to choose particular ad size, here are some tips for better understanding:
- Google allows placing 3 content ads and 3 link unit ads and 2 search boxes on any page complying with AdSense policies.
- Though link ads are listed under content ads and have the same creation process there are certain points to understand before using link ads to fill your ad space. Read our separate article on facts about AdSense link ad units.
- Certain individual ads are restricted to use one unit per page. For example you can place only one ad unit of horizontal banner of ad size 970×90 on a page (besides other ad units).
- Responsive ads adjust the size automatically based on the space available on the viewing device hence suitable for sites with responsive layouts.
- Avoid using custom ad sizes which will result in reduction of revenue since there may not be any bids from the advertisers for your custom size.
Bigger Vs Smaller Ad Sizes
If you are confused on selecting bigger and smaller ads then it is necessary to understand how Google choose the ads to be displayed on your site. The bigger ad sizes automatically fill smaller ad sizes as well if the bid amount of later exceeds the actual ad size selected. We explain this with a simple example here.
Assume advertiser A has chosen to place ads on your site with the below details:
- Ad size – 336×280 Large Rectangle
- Bid amount per click – $0.50
Another advertiser B also choose your site to place targeted ads with the below details:
- Ad size – 300×250 Small Rectangle
- Bid amount per click – $0.75
If you have placed ad size of 336×280 large rectangle on your site, Google will still display the smaller rectangle ad of 300×250 since it has higher bid amount. So as a rule of thumb, always select larger ad sizes to cover more inventories of ads with higher revenue.
This is also true for custom ad size which means any smaller ad size having higher bid will be served to fill your custom ad size.
Finding the Better Choice
If you are not sure about choosing the ad size select the bigger sized one fitting your ad space possibly from the recommended ads. The reason is that recommended ads will have more inventory than other ads ensuring high ad coverage and the possibility of higher revenue.
You also can test with different types of ads or variation within the same size to see which one is generating more revenue.