Since the beginning of digital advertising, publishers, advertisers and internet users have lived with Big Box, Leaderboards and other IAB standard units. These guidelines got more and more complex with the emergence of technologies allowing for “rich”,“expando” and mobile formats that were not optimized for that many pixels to be displayed.

In 2017, the IAB will put an end to this proliferation of pixel ad units and simplify the digital advertising landscape with “Flexible size ads”. No more 300×250, 728×90 and other pixel formats and say hello to ads defined by ratio (1:1, 1:2, 1:3, 2:1, 6:1, etc.). Thus, we will be able to display the same creative on mobile, tablet or desktop in different sizes but with the same proportions!

formats flexible size ads

This change will take effect as soon as 2017, so how should you prepare?


In order to go through this transition as smoothly as possible, the IAB already offers to adopt LEAN ads (Light, Encrypted, Ad choice supported & Non-intrusive). These guidelines, compatible with our current tools, also follow the new formats. It is a first step to this new digital age.

If you already respect IAB guidelines, do not worry: your ads are already LEAN!


The effective date has yet to be announced and the deployment will take place throughout the year.

However, we would all benefit from starting as soon as possible. To this end, the IAB has already published a new ad portfolio. So, for your 2017 campaigns, forget pixels and start thinking in terms of ratio!

If you want to discover all the new formats, download our guide on Flexible Size Ads.

Guide Flexible Size Ads

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