Google Adsense provides you with various different ad formats that can be displayed in varied ad sizes on your web pages. Google provides you with different ad sizes that you can choose from, to better suit your web design. I have classified these sizes to four major categories but you can use any of them anywhere on the webpage.
These are horizontal rectangle ads which can show any of the ad formats. Horizontal ads are the most popular and also the better performing ones. Due to the horizontal size it fits much more easily into most web designs and also follows the same text pattern as the content on the page. This allows these ad sizes to blend better with the content. There are three horizontal sizes that you can choose from
- Leaderboard (728 x 90): A very wide size which spans across the screen on most screen resolutions. These work well when used at the top of the page above the fold and is contained in a row by itself. The ad on top of this page as well the image following this is an example of the leaderboard.
- Banner (468 x60) : This is runs about half the width of the leaderboard and works well beside the logo of the webpage. In case of a blog, you can use this to span the top or the bottom of your blog post.
- Half-banner (234 x 60) : Again half the size of the banner, as the name suggests, it can work well with in the content especially for a blog site. It is also a good fit into the sidebars of a website design, if too much height or vertical space is not available.
These are large rectangular ads which can runs vertically. These can run along the sides of the webpage but does not blend in quite as much as the horizontal sizes. There are limited areas in a web design that you can Even then, these are pretty popular.
- Wide Skyscraper (160 x 600) : These are slightly wider than a typical skyscraper and works well on either side of the web content. The ad which is to the left of this content is an example of a wide skyscraper.
- Skyscraper (120 x 600) : These works just as well as the wider one, but are appropriate when the space is at a much more premium.
- Vertical Banner (120 x 240) : These run just as wide as the typical skyscraper, but is much shorter in height. These do not display image ads.
These are ads which are perfect squares. Many websites stack them to create a larger square or larger rectangle. Stacking them gives you the advantage of having able to show multiple text ads rather than just one bigger sized ad which might suit your web design.
- Button (125 x 125) : These are pretty small squares but are perfect to stack as a group. Currently, image ads are not supported in the smaller size.
- Small Square (200 x 200) :This is a medium size square which is quite versatile to fit in most places including the sidebars and inside the content. If you have a large enough header, it could fit there as well.
- Square (250 x 250) : A larger square which should probably displayed above the fold and on the side of the content or inline with the content with wrapping text.
Even though the Horizontal and vertical ads are also rectangles, these ad sizes are much more squarish than wide rectangles and hence I have classified them separately. These “larger squares” have been known to perform better than the square ads itself on many sites.
- Small Rectangle (180 x 150) : A odd sized rectangle which falls somewhere between a button and small square. Inline with the content is probably a good place
- Medium Rectangle (300 x 250) : Bigger than the square, this can be on the sidebar if your design has a wide enough sidebar.
- Large Rectangle (336 x 280) : This is often touted as the best performing of all the square and rectangle ads.
The suggestions for ad placements are pretty generic and they are just mere suggestions. You might want to fine tune them depending on your website design or blog theme layout. It is also useful to take a look at the heatmap generated by Google, to get more ideas about ad placement.
Some ad sizes perform much better than others in general, but that does not mean what works for one website works for an another. The performance of a ad size is very dependent on the website itself, so you should first choose a set of sizes that fits your web design for each slot and then choose the best performing one from that set for each slot.