What is the 30% Ad Density Rule? And Why Should You Care?

As a publisher, you may not be able to look at your website as an average user anymore. However, take a step back and evaluate your site… and you’ll probably understand why users install ad blockers.

Ad blockers decimate the earning potential of publishers. In order to improve user experience and curb the adoption rate of ad blocking, the Coalition for Better Ads created the Better Ads Standard.

On mobile devices, a new rule stipulates how much screen space can be occupied by ads. But publishers often get confused by this because mobile devices have different screen sizes even within the same brand.

So, What is the 30% Ad Density Rule?

According to the Coalition for Better Ads:

Ad density is determined by summing the heights of all ads within the main content portion of a mobile page, then dividing by the total height of the main content portion of the page. For mobile devices, ad density cannot be higher than 30%. Meaning, ads that take up more than 30% of the vertical height of a page are intrusive.

So, if the total height of your webpage (with ads) is 1000px, then the cumulative height of ads on the page should be less than 300px.

This is calculated by adding the heights of all units in the content section. For instance, if three ad unitsーA, B, and C—are used. Then the sum of their heights should be less than 300px to comply with Better Ads Standard.

Key Points of 30% Ad Density Rule

• The ad density of a mobile webpage is measured in pixels (px). And it is calculated with respect to the entire content section rather than the viewport of the mobile screen
• The main content section of the page excludes the header, footer, and navigation panel(s) containing related article or navigation links
• Ads outside the main content section (for instance, a leaderboard ad next to the website logo) are not included in the ad density calculation
• All ad formats including text, image, video in form of sticky, interstitial, inline, and more are placed in the ad density calculation formula
• If the video content on the page contains pre-roll and/or mid-roll ads, then it will be considered as a part of the content and not calculated in the ad density measurement

Beyond the 30% Ad Density Rule

30% ad density rule is just one of the many recommendations made by the coalition, according to the standard, publishers should avoid using the following ad types on mobile devices:

• Pop-up ads
• Large sticky ads
• Flashing animated ads
• Auto-playing video ads with sound
• Ad density higher than 30%
• Full-screen ads with countdown

This report was generated by the Coalition for Better Ads by surveying 66,000 web users. With their efforts, the coalition wants to improve the quality of ads around the web. Publishers can become compliant by auditing their sites. Focus on following the standards and creating a better ad experience. Inspect your existing ads and eliminate the most disruptive types. Work on creating different ad layouts for mobile and desktop versions of the site. These changes may cause a dip in your ad revenue, but in the long run, it will protect you from being suddenly blacklisting by ad partners.

What’s Next?

In order to support the coalition, Google will stop showing ads on websites that use disruptive ad formats after 9th July 2019. Since Chrome has more than 62% market share, this may result in a sharp drop in revenue for non-compliant publishers. Google may also blacklist such sites.

How to be ready? Generate an Ad Experience Report with Google and fix the issues. Ask for another review once you are done fixing the old ones, this will avoid your site from being blacklisted by Chrome.

The coalition was formed in January 2017, which makes it a relatively new collaboration. Nevertheless, given the number of ad tech giants backing it, publishers will do well by staying up-to-date with the latest standards and recommendations released by this industry body.