An interstitial ad is a full-screen ad that appears between sessions, content, or natural break points in a mobile app. Unlike rewarded video, interstitials are forced-view — the user didn't opt in; the ad just appears. This makes them lower-quality from an advertiser perspective (less attention, lower brand-recall) but still much higher-eCPM than banner ads. Interstitials are the workhorse format for games and content apps that have natural transition points.
Where interstitials live naturally
- Between levels in games — the canonical use case. Show after the user completes a level, before they start the next.
- Between content pieces — after finishing an article, before the next one. Common in news / content apps.
- At natural session boundaries — after the user navigates back to the home screen from a deep state.
- At app open — controversial. Apple's App Review Guidelines restrict app-launch interstitials (impede the user's primary intent); Google Play has more relaxed policies.
- At app close / backgrounding — some apps show interstitials when the user backgrounds the app. Edge case, can feel intrusive.
eCPM ranges (US iOS, 2026 anchors):
- Interstitial video: $5-15. Most common form, often called "video interstitial".
- Interstitial static (image-only): $3-10. Lower eCPM than video.
- Playable interstitial: $8-20. Interactive mini-experiences. Higher engagement, higher payout, but require more complex creative production.
Geo and category matter — same format in India Android can run $0.30-1.00, Western Europe iOS $3-8.
Frequency capping is everything: too many interstitials crater retention, drive uninstalls, and ultimately reduce revenue (fewer users → less total ad inventory served). Sweet spots:
- Casual / hyper-casual games: 3-5 interstitials per session, typically at level boundaries.
- Mid-core games: 1-3 interstitials per session, at less-frequent natural breaks.
- Content apps: 1-2 interstitials per session, between content pieces.
- Productivity / utility apps: typically zero — interstitial timing rarely fits.
Most mediation platforms (AppLovin MAX, ironSource) expose per-user frequency capping. Set it conservatively, A/B test variants, watch retention impact.
Platform policies to know
- iOS App Review Guideline 4.2.4 (apps): ads must not be hidden, deceptive, or interruptive of user-initiated actions. Apple has historically been strict on app-launch interstitials.
- Google Play Policy: more permissive on placement but restricts "unexpected ads" — interstitials that appear in surprising places or are hard to dismiss.
- App Store / Play Store both ban: ads that block the close button, ads with deceptive "x" / close buttons that actually open the ad, ads that mimic system UI.
Common pitfall: chasing eCPM by cramming in more interstitials. Short-term revenue lifts, but D7 retention drops 10-30%, uninstall rate spikes, and total lifetime revenue per user drops. Track integrated revenue × retention, not raw interstitial CPM.