Best Practices: Don't miss out on interstitials

June 20, 2012

Tags: 2012

masthead mobile
Caitlin McGovern


See all blog articles

Historically, the most common ad format used for mobile monetization has been the banner ad, also known as a 320×50 ad unit. Banners were an easy carry over from desktop advertising but with recent improvements in resolution, display, bandwidth, rich media standards, and growth in the mobile ad market in general, publishers are increasingly shifting their inventory to interstitials. Publishers are using 320x480s, also known as a full-screen ad unit, and 300x250s, also known as a medium rectangle ad unit (or “m-rect” as we refer to them). Since there are a variety of different Android device sizes, the MoPub SDK automatically scales the full-screen ad unit to fit that device size.

The conversation surrounding the use of interstitials as a mobile monetization strategy has turned to interstitials for a variety of reasons. The most obvious reason being higher engagement rates with interstitials, measured by the ubiquitous click-through rate (CTR).

Ad networks and DSPs use a publishers’ CTR as a means for determining the CPM. As publishers integrate more and more interstitials into their applications, we have noticed that these ads units have higher CTRs and higher eCPMs than banner ad units. Typical banner ad units have a fill rate of 80-90%, a CTR of .10-.76%, and an average eCPM of about $0.70-1.00. Most importantly, we’ve seen demand for interstitials on MoPub Marketplace and thereby, eCPMs, rise considerably as advertisers and their representatives increasingly turn their spend to mobile.

When publishers begin to integrate interstitials, there is often the question of whether to implement a 320×480 ad unit or a 300×250 ad unit. From what we have seen, 320×480 ad units have a fill rate of approximately 10-15%, have a click-through rate of 2-6%, and have an average eCPM of about $1-3. On the other hand, 300×250 ad units have a fill rate of approximately 20-30%, have a click-through rate of .20-.96%, and have an average eCPM of about $.80-1.50.

Once interstitials are integrated into your applications, it’s also important to note which ad networks support 320×480 and 300×250 ad units through the MoPub integration. Jumptap, Millennial, Greystripe, and Tapit, all support both a 320×480 and a 300×250. InMobi supports both ad units, but interstitials are only supported via the InMobi SDK. Brightroll supports only iOS interstitials, and iAd only supports interstitials on the iPad. Lastly, AdMob also supports both ad units, but a publisher needs to have Google’s approval for interstitial support. We’re constantly updating this list on our ad networks support page, but you can always email if you have specific questions.

Want your questions answered?  Email us at or Tweet @mopub with suggested topics.


Contact us

Contact us

Ready to maximize your mobile revenue?

Girl with phone