Curated by: Luigi Canali De Rossi

Friday, September 12, 2008

Online Standard Ad Formats: Official Advertising Formats And Sizes For Web Banner Ads

Banner, leaderboard, skyscraper, small rectangle. Just like for newspapers and print magazines, also on the Web advertisers and publishers have defined over time an official set of "online standard ad formats". Such ad formats represent the full range of visual and text-ad sizes available for use on public web pages.

Photo credit: Marc Dietrich edited by Daniele Bazzano

If you are a web publisher, blogger or other media outlet on the Internet, and are interested in monetizing your published assets, you may want to familiarize yourself with this illustrated list of standard online ad formats.

By knowing with are the standard ad formats to be utilized on web pages, you can:

a) Brief more effectively your web designer when in need of creating new ad areas

b) Offer more ad opportunities to your own direct customers

c) Utilize the standard "creatives" that your customers may have designed for other campaigns (without requiring them to design custom sized ads for your site only)

d) Tap into the opportunities offered by ad networks, who rely heavily on these specific ad formats

Officially, the standard online ad formats you see on the web today, have been originally established by the IAB (Interactive Advertising Bureau) , an authority founded in 1996 to increase the quality level of the advertising marketplace in the US.

The most common online ad formats are banners, flashing or animated ads on the top of the screen, skyscrapers, vertical usually found at the left or right side of a web page, or the square box, which is found in the majority of Web 2.0 sites like Mashable! or ReadWriteWeb.

Standard ad formats are the heritage of the print advertising medium in which advertising agencies have long established a fixed, common structure for advertising spaces, to manage orders ad productions costs more efficiently.

The main references for online standard ad formats are the IAB's Ad Unit Guidelines and Google AdSense Ad Formats which have been directly derived from the already existing ones.

For online ad formats all dimensions are always measured in pixels and the recommended file weight is about 20-40k.

In this mini guide you can find a visual gallery of all the standard, official, ad formats utilized on the Internet.




Online Standard Ad Formats

Rectangles and Pop-Ups

  • Medium Rectangle - 300 x 250


    This is one of the more common ad formats on the web. Its main characteristic is to be well-integrated into content, associating your message with highly specific site-related articles. Dimensions can slightly vary but they should not exceed 360px in width and 300px height. Maximum file size for Rectangles should not exceed 50kb.

  • Square Pop-Up - 250 x 250


    Despite being very profitable for advertisers, users find them very annoying. Pop-up ads usually open in a new window and you usually need to close them before you can view the page's content. That's why almost any browser now includes a pop-up blocker by default.

  • Vertical Rectangle - 240 x 400


    One of the newest formats introduced by IAB. It combines the usual rectangle characteristics with a bigger size. It can be placed either at the right or left side of a web page.

  • Large Rectangle - 336 x 280


    A larger version of the rectangle ad. Well-integrated into content, provides highly site-related ads and is immediately visible to users.

  • Rectangle - 180 x 150


    A smaller version of the classic rectangle ad. Well-integrated into content, it should be providing highly relevant ads to the readers.

  • 3:1 Rectangle - 300x100 *NEW*


    One of the most recent ad formats introduced by IAB. Very similar to the banner ad but larger in size.

  • Pop-Under - 720x300 *NEW*


    Pop-under ads are very similar to pop-ups. Tough they generally annoy users less because they appear in a new minimized window, instead of a bigger flashing box, in my opinion they really suck. Stay clear of them as people get really pissed off at these. As a matter of fact, often readers don't even notice such pop-unders until they close the main browser window. And in any case, remember: Just like standard pop-ups, pop-unders are blocked by pop-up blocker software.


Banners and Buttons

  • Full Banner - 468 x 60


    The classic 468 x 60 pixel banner is the workhorse of web advertising. It is found in the vast majority of sites and is still one of the biggest money makers because of its very popular and effective above-the-fold positioning which provides exceptional visibility.

  • Half Banner - 234 x 60


    Half the size in width of a classic 468 x 60 banner, it provides the same benefits of visibility while being less intrusive.

  • Micro Bar - 88 x 31


    The less intrusiv ad format of all. Its above-the-fold positioning provides good visibility without disrupting user's experience. Very well-integrated into site content.

  • Button 1 - 120 x 90


    Buttons are kind of square-shaped ads that usually enclose links to interesting products for users. They are also very non-intrusive

  • Button 2 - 120 x 60


    Slightly larger than the Micro Bar ad, this button supplies the same features of visibility and integration into the site content while resulting less intrusive.

  • Vertical Banner - 120 x 240


    The same as the classic horizontal banner ad, but vertically oriented. Visible and not very intrusive.

  • Square Button - 125 x 125


    Slightly bigger ad format than the Button 1. Maximum file size per Square Buttons should not be more than 15kb.

  • Leaderboard - 728 x 90


    Leaderboards are very common in sites as they provide very good visibility. Slightly larger than banners ads, normally appear at the top of the page. They allow advertisers to usually use regular-size banners in the same space, so they are easy to work with. Width may range between 468 and 750 pixels and height may range between 60 and 100 pixels. Maximum file size should never exceed 25kb.



  • Wide Skyscraper - 160 x 600


    A high impact ad usually displayed at the right side of the screen. Skyscrapers are becoming more and more common as a less intrusive way to attract users who are annoyed by the banners ads. Skyscrapers should always be less than 800px in height and 160px in width. Maximum file size should be equal or less than 35kb.

  • Skyscraper - 120 x 600


    Smaller in width than the usual format of skyscraper ad, the 120 x 600 ad is very useful when visualized on lower resolution screens.

  • Half Page Ad - 300 x 600


    Very intrusive ad usually placed at the right or left side of a web page. It provides good visibility but it may result annoying for users who have a large part of the screen occupied by such an advertisement.



  • Video and audio banners should be initiated by a users' action. The user should mouse over or click on the ad before any video or sound is played.
  • There should be at least a 1 second delay between frames in GIF or JPG animations.
  • Characters in the ads should never be more than (including spaces) 100 for little ad formats like Buttons or Banners and 200 for larger ads such as Leaderboards or Skyscrapers.
  • Ads code should serve a backup GIF file in case the browser does not support Flash or Shockwave animations. Users should never be asked for installing plug-ins. The ad code should automatically recognize if the necessary plug-in is activated and display animations of GIF file according to that.
  • Due to the differences in how Macs and PCs render pop-up menus and text entry fields, please allow extra horizontal space so that ads do not extend beyond their intended width or height.
  • Since all browsers do not support Java, and the user can disable it, banner codes must be degradable and must serve a backup GIF file.


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Originally written by for Master New Media and first published on September 12th 2008 as "Online Standard Ad Formats: Official Advertising Formats And Sizes For Web Banner Ads".

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posted by Daniele Bazzano on Friday, September 12 2008, updated on Tuesday, May 5 2015

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This work is licensed under a Creative Commons License.




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