Responsive banner ads have variable widths so their size is defined by their height only. The following seven sizes provide a nice range of heights suitable for almost any situation.
Below are the most common static banner sizes. These have fixed widths and heights in pixels.
* Normally the vertical Banner is 240px high but 250px is close enough. I chose 250px over 240px because the 300 x 250px banner is a lot more common then the Vertical Banner. It is important to limit the number of common heights so the job of creating responsive banners is as easy as possible. There is no need to have two standard heights so close to each other.