How to Create Custom Ad Sizes in Google Adsense1. Go to the Adsense account and "Sign In" to access your account.
2. Click on the "My Ads" tab at the top of your Adsense account page. Click the "New Ad Unit" button in the top left of the "My Ads" section.
4. Add the height and width of the ad unit which you want to create. Click "Save and Get Code" to save the add and obtain the embed code to add it to your website or blog.
The following size restrictions will be enforced:
- 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.