What Is an Interstitial Ad?
An interstitial ad is a full-screen advertisement that appears between content transitions, covering the entire interface before the user proceeds to their intended destination. Common in mobile apps, games, and mobile web, interstitials appear at natural break points such as between game levels, after completing a form, or during app loading screens. Because they occupy the full viewport, they command near-total attention, making them among the highest-visibility formats in digital advertising.
How Interstitial Ads Work
Interstitials trigger at predefined transition moments. A user taps “Next Level” in a mobile game, and before the level loads, a full-screen ad appears for a set duration, typically 5 to 30 seconds, with a close button appearing after a delay. The sequence follows a consistent pattern:
- User initiates a content transition
- Ad renders over the full screen
- A countdown or close button appears (often after 5 seconds)
- User dismisses the ad or taps through to the advertiser
- Original content loads
Formats include static image, HTML5 animated, video, and playable ads. Playable interstitials, where users interact with a mini-demo before downloading an app, are particularly common in mobile gaming. Vungle, now rebranded as Liftoff, reported in its 2023 mobile gaming benchmarks that playable interstitials generated 2x to 5x higher install rates compared to standard display formats in the same placements.
Key Metrics and Benchmarks
| Metric | Interstitial Average | Banner Ad Average |
|---|---|---|
| Click-Through Rate (CTR) | 2%–5% | 0.1%–0.35% |
| CPM (Mobile, US) | $4–$12 | $0.50–$1.50 |
| Viewability | ~95%+ | ~50%–60% |
| Avg. Close Rate (before 5s) | ~15%–25% | N/A |
Because interstitials are inherently viewable, they sidestep many of the viewability issues that plague standard banner inventory. The trade-off is a higher risk of accidental clicks and user friction if placements are poorly timed.
eCPM Calculation for Interstitial Ads
Publishers and app developers evaluate interstitial performance using effective cost per thousand impressions (eCPM):
eCPM = (Total Ad Revenue / Total Impressions) x 1,000
For example, an app serving 500,000 interstitial impressions per month generating $3,500 in revenue produces an eCPM of $7.00. Compared to banner eCPMs that often fall below $1.00 in the same app, interstitials typically deliver three to ten times the revenue per impression. That gap is why they remain a primary monetization tool for free-to-play mobile games, even with the intrusiveness trade-off.
Google and Platform Policy Constraints
Interstitials are subject to strict platform policies that advertisers and publishers must follow to avoid penalties. Through its Better Ads Standards initiative, developed with the Coalition for Better Ads, Google identified several interstitial types that degrade user experience and trigger search ranking penalties on mobile:
- Popup interstitials that appear immediately after a user navigates from search results
- Standalone interstitials that must be dismissed before accessing content
- Above-the-fold layouts that visually mimic interstitials while embedding the page below
Google’s January 2017 mobile interstitial penalty update specifically targeted these patterns on mobile web. App interstitials served through Google AdMob follow separate enforcement guidelines under Google Play’s ad policy framework, which prohibits interstitials that trigger unexpectedly or block access to core app functionality.
Apple’s App Store guidelines similarly restrict interstitials that appear at app launch or during active gameplay without a clear dismissal mechanism.
Interstitial Ads in Mobile Gaming
The mobile gaming sector accounts for the largest share of interstitial ad spend. Games like Subway Surfers, developed by Sybo Games, and Candy Crush Saga from King (a subsidiary of Activision Blizzard) built substantial revenue streams by placing interstitials at natural pause points between game rounds and lives. King reported advertising revenues of approximately $136 million in 2022, with interstitials comprising a meaningful portion of that figure alongside rewarded video.
The rewarded video format has grown as a user-friendlier alternative within the same interstitial placement structure. Unlike forced interstitials, rewarded units offer the user an in-game benefit (extra lives, coins, power-ups) in exchange for watching a video. This opt-in mechanic generally produces lower friction and higher completion rates, often exceeding 85%, compared to skippable interstitials.
Frequency Capping and User Experience
Frequency capping is critical to sustainable interstitial monetization. Showing interstitials too often accelerates churn. That’s a costly outcome in apps where customer acquisition cost (CAC) can range from $1 to $5 per install for casual games.
Industry practice generally recommends a minimum of one interstitial per three to five user actions or sessions, though optimal frequency varies by app category and audience segment. AppsFlyer’s 2023 Mobile Gaming Apps Report found that aggressive ad frequency has measurable consequences. Apps showing more than one interstitial per two minutes of session time saw day-7 retention rates drop by as much as 20% compared to apps with moderated frequency.
Interstitials on Desktop and Web
On desktop, interstitials appear primarily in media and publishing. Sites like Forbes and Time historically used “welcome interstitials” that displayed a full-page ad before the article loaded, with a “Continue to site” button. These formats faced backlash and rising ad blocker adoption through the mid-2010s. Forbes reported in 2016 that approximately 42% of its desktop audience used ad blockers, a figure widely cited as a direct consequence of intrusive interstitial use.
Most major publishers have since migrated toward less disruptive formats or reduced interstitial frequency on desktop, while mobile web interstitials remain more prevalent due to the smaller screen context making the format feel proportionally more native.
When to Use Interstitial Ads
Interstitials perform best when the following conditions are met:
- Placement aligns with a genuine content transition (level end, form completion, article load)
- The close button is clearly visible within 5 seconds
- Frequency is capped to prevent session fatigue
- Creative is high quality and relevant to the audience
- Campaigns prioritize cost-per-install (CPI) or cost-per-acquisition (CPA) goals where higher engagement justifies the CPM premium
For brand awareness campaigns seeking broad reach at lower cost, interstitials may not offer the best efficiency. For performance-focused mobile app install campaigns, the format consistently outperforms standard banners on a return-on-ad-spend basis when placement quality is controlled.
Interstitial Ad FAQs
What is an interstitial ad?
An interstitial ad is a full-screen advertisement that appears between content transitions and covers the entire screen before the user reaches their destination. The format is most common in mobile apps and games, appearing at natural pause points such as between game levels or after completing a form.
Are interstitial ads effective?
Interstitial ads are among the most effective formats in digital advertising by measurable engagement. They deliver CTRs of 2% to 5%, compared to 0.1% to 0.35% for banner ads, and viewability rates above 95%. The trade-off is user friction: poorly timed placements increase churn and can hurt long-term retention metrics.
What is the difference between an interstitial ad and a banner ad?
A banner ad occupies a fixed portion of the screen and does not interrupt the user’s session, while an interstitial ad covers the full screen and requires active dismissal. Interstitials generate significantly higher CPMs ($4 to $12 versus $0.50 to $1.50 for banners) but carry a higher risk of user frustration if overused.
Do interstitial ads violate Google’s policies?
Certain types of interstitial ads do violate Google’s Better Ads Standards, specifically those that appear immediately after a user arrives from search results or those that block content without a clear dismissal option. App interstitials served through Google AdMob are governed by separate Google Play ad policy guidelines with their own enforcement rules.
What is a good eCPM for interstitial ads?
A good eCPM for interstitial ads in the US mobile market typically ranges from $4 to $12, with variation by app category, audience quality, and ad format. Playable interstitials in mobile gaming tend to push eCPMs toward the higher end, while lower-quality placements on general apps often sit at the lower end of that range.