Google has announced a new feature that makes it possible for publishers using AdSense to create their own custom ad sizes. The custom sizes are applicable to both text and display ads.
Google will determine the number of text ads that appear in an ad unit, and may change the results for a given impression. According to the announcement, the Google “system predicts the value of each competing ad for every impression, based on historic performance and comparison across a variety of scenarios.”
With display ads, the Google system determines the appropriate ad size to fit in the space selected. The screenshot below shows how display ads can render within custom ad units — illustrated by dotted lines here for illustration purposes only.
There are limitations to what you can do with custom ad sizes. The new size restrictions include:
- Only one dimension can be greater than 300 pixels
- The minimum width is 120 pixels
- The minimum height is 50 pixels
- Neither height nor width can exceed 1200 pixels.
To set up custom AdSense ads on your site, select “Custom ad size” from the Ad Size drop down and set the height and width specifications you want.