IAB Ad Unit Guidelines

The IAB Ad Unit Guidelines are intended for marketers, agencies and media companies for use in the creating, planning, buying and selling of interactive marketing and advertising. The IAB’s Ad Sizes Working Group will meet on a bi-annual basis to review proposed new ad units and issue updated voluntary guidelines as appropriate.  The process whereby these new units are reviewed and considered can be downloaded here.

The IAB Ad Sizes Working Group will also provide updated recommended file weights for each unit, to be completed in Q3, 2007.

*All specifications below are in pixels

These voluntary guidelines provide a framework for advertising inventory and web page design. The goal is to reduce and simplify the amount of work for agencies that may be faced with having to create several assets of a similar size for different publishers, e.g. 300×95, 300×100, 300×105.

You are encouraged to examine the standardized units and consider them for inclusion into your product offerings.

Agencies & Advertisers
As you expand and utilize greater creativity in your interactive messaging, these Guidelines suggest various units that are being introduced or offered by various publishers.  Please consult your partners to understand their full creative specifications.

We also encourage agencies to use the IAB Creative Spec Database as a simple, easy-to-use centralized source of interactive advertising creative specifications. 

Those sizes that are bold below are part of the Universal Ad Package


Rectangles and Pop-Ups

300 x 250 IMU – (Medium Rectangle)
View IMU

250 x 250 IMU – (Square Pop-Up) View IMU

240 x 400 IMU – (Vertical Rectangle)
View IMU

336 x 280 IMU – (Large Rectangle)
View IMU

180 x 150 IMU – (Rectangle)
View IMU

*NEW* 300 x 100 IMU – (3:1 Rectangle)
View IMU

*NEW* 720 x 300 IMU – (Pop-Under) View IMU

Banners and Buttons

468 x 60 IMU – (Full Banner)
View IMU

234 x 60 IMU – (Half Banner)
View IMU

88 x 31 IMU – (Micro Bar)
View IMU

120 x 90 IMU – (Button 1)
View IMU

120 x 60 IMU – (Button 2)
View IMU

120 x 240 IMU – (Vertical Banner)
View IMU

125 x 125 IMU – (Square Button)
View IMU

728 x 90 IMU – (Leaderboard)
View IMU


160 x 600 IMU – (Wide Skyscraper)
View IMU

120 x 600 IMU – (Skyscraper)
View IMU

300 x 600 IMU – (Half Page Ad)
View IMU

Other Information:
Please consult these additional creative guidelines for more information:

IAB Digital Video Creative Guidelines
IAB Pop-Up Guidelines
IAB Rich Media Guidelines
IAB Universal Ad Package


IAB Issues Pop-Up Ad Guidelines for Industry Comment

New York, NY (April 29, 2004) – In the first effort of its kind to address the use of the pop-up and pop-under online ad formats, the Pop-Up Task Force of the Interactive Advertising Bureau (IAB) today issued voluntary guidelines and best practices intended to improve the online marketplace. These guidelines will be posted on the IAB site and the industry (advertising agencies, marketers, online publishers and technology vendors) will be asked to comment on the recommendations. The comment period will last for the next two months. Following a review of the feedback, the guidelines will become final.

“IAB is hopeful that these guidelines will improve the medium overall by promoting more responsible use of these ads, thus enhancing the consumer experience,” noted Greg Stuart, CEO, IAB. We are especially keen to receive feedback on the frequency cap, which recommends only one pop-up/under per user session, as research has shown frequency to be a key issue for consumers.”

In creating these best practices, the IAB reviewed extensive research regarding user sentiment and acceptance. The findings provided a roadmap to creating guidelines that will be most palatable for consumers while maintaining the market for advertisers. Among other key findings, from the period March 2003 – February 2004, pop-ups comprised approximately 6% of all U.S. online ad impressions (Nielsen//NetRatings AdRelevance). In regard to consumer perception of pop-ups, approximately 83% of respondents in a study by Planet Feedback, cited pop-ups as “annoying” (Intelliseek/PlanetFeedback Consumer Trust in Advertising Study.)

The pop-up and pop-under guidelines are self-regulatory, and are intended to improve consumer perception of pop-ups by applying consistency in their use, specifications and labeling. In addition, these new parameters will lend efficiency to the online ad creation and buying processes by providing advertisers and their agencies the ability to develop both responsible and consistent advertising content.

After reviewing buyer needs, reviewing ad effectiveness and user acceptance research, the IAB is recommending the following set of guidelines and definitions for pop-up/under advertising:

After reviewing buyer needs, reviewing ad effectiveness and user acceptance research, the IAB is recommending the following set of guidelines and definitions for pop-up/under advertising:

Definition: Any advertising experience that utilizes a web-browser initiated additional window to deliver an ad impression either directly above or below the existing browser experience.

Frequency: Each user should be exposed to no more than one pop-up ad for each visit to an online site.*

Labeling: Both pop-ups and pop-unders should be clearly labeled with the name of the Network / Advertiser – Publisher – Browser Type ( if applicable): Example:



Unit Type

Unit Size
(WxH in pixels)

File Weight


Close Box



50k images
50k flash

User initiated




30k images
40k flash

User initiated


Pop-Up Large


30k images
40k flash

User initiated


Note: Not all publishers carry either pop-ups or pop-unders. Some publishers may not accept all ad sizes. *Technical frequency guideline: One per user per session per site for both pop-ups and pop-unders. Ad networks and servers may either count a session by site or across network.

The IAB Task Force is led by Rich LeFurgy, Archer Advisors and Scot McLernon, CBS MarketWatch. Participating companies include: About, Inc., Adtegrity, Advertising.com, Archer Advisors, AOL, BizRate.com, CBS Sportsline, CNET Networks, CondeNét,, Electronic Arts, FastClick, Focus Interactive, Forbes.com, Homestore.com, Interpolls, MSN, MTV Networks, NY Times Digital, Terra Lycos, Traffic Marketplace, Reuters, Unicast, United Virtualities, ValueClick, Viewpoint, Wall Street Journal Online, Walt Disney Internet Group,
Washingtonpost.Newsweek Interactive, weather.com and Yahoo!

The IAB does not condone nor endorse any online ad format. With respect to voluntary guidelines, it suggests thoughtful and well-researched recommendations that will improve the overall online ad business.

About the IAB:

Founded in 1996, the Interactive Advertising Bureau (IAB) represents the leading companies in the interactive space. Membership includes companies that are actively engaged in, and support the sale of interactive advertising in addition to being responsible for selling over 85% of online advertising in the United States IAB members include AOL, CNET Networks, DoubleClick, MSN, Google, Overture, The Walt Disney Internet Group, Yahoo! and over 150 others.   On behalf of its members, the IAB evaluates and recommends standards and practices, fields interactive effectiveness research and educates the advertising industry regarding the use of interactive advertising.  For more information on the IAB please visit www.iab.net.

Marla Nitke IAB

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