All formats of Adsense display Ad Blocks
There are different sizes for the display Ad Blocks which you can use on your site. I will summarize the sizes below. I also added full size templates to give you a good idea of the sizes.
Sizes of Horizontal Ad Blocks
728×90 px Leaderboard
320×100 px Big Banner for Mobile
970×250 px Billboard
970×90 px Big leaderboard
468×60 px Banner
320×50 px Mobile Banner
234×60 px Small Banner
Sizes of Vertical Ad Blocks
300×600 px Big Skyscraper
300×1050 px Portrait
160×600 px Wide Skyscraper
120×600 px Skyscraper
120×140 px Vertical Skyscraper
Sizes of Rectangle Ad Blocks
336×280 px Large Rectangle
300×250 px Medium Rectangle
250×250 px Square
200×200 px Small Square
180×150 px Small Rectangle
125×125 px Button
Responsive Ad Blocks
The Responsive ad adapts to the size of the screen, it can have any of the above ad sizes.
Custome Sized Ad Blocks
You can also state custome sizes for your ad blocks. It however isn’t recommended, as there will probably not be many advertisers who want to advertise in these formats. it would probably be better to use responsive ads for deviant ad spaces.
Sizes of Link Blocks
Apart from display Ads you could also show Link Blocks on your website. These Blocks also have different sizes. I state them below:
728×15 px Horizontal Large
468×15 px Horizontal Medium large
200×90 px Vertical Extra Large
180×90 px Vertical Large
160×90 px Vertical Medium Large
120×90 px Vertical Small
Guidelines for showing display Ads on one webpage
In short you are allowed to put three different Display ads on one webpage at a time and furthermore you are allowed to have 3 different link blocks and a search box on the same webpage. That is of course maximum and not Always recommended. For all details and guidelines visit the Google Support pages for Adsense.
Best of Luck
Robert Wiebenga