IAB recommends 4 ad sizes for the web

The IAB has the majority of large US websites as members and has the support of the American Association of Advertising Agencies. These recommended 4 sizes are collectively called the Universal Ad Package (UAP) and compliant websites can be identified by an UAP Compliance Seal.

Here follows a list of ad sizes prevalent in the US. The sizes recommended by the IAB are underlined:

Rectangles and Pop-Ups

300 x 250 IMU - (Medium Rectangle)
250 x 250 IMU - (Square Pop-Up)
240 x 400 IMU - (Vertical Rectangle)
336 x 280 IMU - (Large Rectangle)
180 x 150 IMU - (Rectangle)

Banners and Buttons

468 x 60 IMU - (Full Banner)
234 x 60 IMU - (Half Banner)
88 x 31 IMU - (Micro Bar)
120 x 90 IMU - (Button 1)
120 x 60 IMU - (Button 2)
120 x 240 IMU - (Vertical Banner)
125 x 125 IMU - (Square Button)
728 x 90 IMU - (Leaderboard)

Skyscrapers

160 x 600 IMU - (Wide Skyscraper)
120 x 600 IMU - (Skyscraper)

The IAB member companies that are currently, or plan to be compliant in the next 12-18 months, include: 24/7 Real Media, About, America Online, CBS SportsLine.com, Classmates Online, CNET Networks, CondeNet, Edmunds.com, The Excite Network, Forbes.com, iVillage, MarketWatch.com, Meredith Corporation, MSN, New York Times Digital, Terra Lycos, Univision Online, USAToday.com, Wall Street Journal Online, The Walt Disney Internet Group, Washingtonpost/Newsweek Interactive, The Weather Channel Interactive and Yahoo!.

These sizes are not very prevalent within South Africa and we eagerly wait for direction from the South African Online Publishers Association being launched officially this week - see Clarity on the launch of the Online Publishers Association.