Even though web ad banners can be created in any size you like, most websites will allow only banners of a particular size range into their sites. So before spending money on hiring the services of a designer, ascertain the sizes of the banner which the ad network or the websites where you wish to display your banner, will accept. Web banner sizes are “standardized” as outlined by the Interactive Advertising Bureau.

There are various formats known as standard banner size for designing web ad banners. These standards have evolved from guidelines worked out by several market leaders in the past. Even though each individual has the liberty to define his/her own format it is advisable to choose the standard formats for the banners in correspondence with most advertisers.

Here is a list of standard web ad banners in exact dimensions of width and height with their special names.

First dimension is always the width of the banner and the width and height are measured in Pixels.

Most commonly used banner sizes are:

Full banner            : width 468xheight60 pixels
Half banner           : 234x60 pixels
Button 1                 : 120x90 pixels
Button 2                 : 120x60 pixels
Vertical Banner     : 120x240 pixels
Micro Button         : 88x31 pixels
Button                    : 80x15 pixels
Square                   : 250x250 pixels
Square Button      : 125x125 pixels
Skyscraper            : 120x600 pixels
Wide Skyscraper  : 160x600 pixels

Other standard web ad banner sizes follow:
Full banner with navigation bar: 392x72 pixels

Rectangle                                       : 400x260, 180x150 pixels
Medium rectangle                        : 300x250 pixels
Vertical rectangle                         : 240x400 pixels
Large Rectangle                            : 336x280 pixels
Half square banner                       : 150x150 pixels
Head banner                                  : 745x100 pixels
Leader board                                 : 728x90 pixels

The Interactive Advertising Bureau (IAB) has issued certain voluntary banner ad size guidelines which provide a framework for advertising inventory and webpage designs. The aim is to lessen and simplify the quantity of work the banner designers might face with having to generate many assets of a similar size of banners for various publishers, for example 300x100 pixels, 300x105pixels, 300x110 pixels and so on.

Even if the various sizes of ad banners are known to you it is not an easy task to assess which ad sizes give the best results, the highest click-through rates, maximum earnings and where should they be displayed for getting optimal results. However, to help you, there are general guidelines and studies that provide you with tendencies that you may consider as a starting point.Various studies show that the best performing ad size is the large rectangle measuring 336x280 pixels.

At the same time they stress the need of using the format that fits your own website best, Considering the wider formats with the best results, the top three places go to the banners, large rectangle of the size 336x280 pixels, medium rectangle 300x250 and the third, wide skyscraper 160x600. The leaderboard size with 728x90 is also gaining popularity as a favorable ad banner For your information, wider banner sizes just tend to produce better results, they may not. Keep in mind, select a banner format that is well-suited to the website where it will be displayed.