What is Interstitial Ads?
Also known as: Interstitials, Full-screen ads
What is an interstitial ad?
An interstitial ad is a full-screen ad that appears between two content moments inside an app or on the web. It covers the entire viewport, holds for a few seconds, and gives the user a close button. Mobile interstitials average 1 to 3 percent CTR, roughly six times the rate of standard banner ads, per Google AdMob benchmarks.
The format trades reach frequency for attention. A banner runs the whole session at low CTR. An interstitial fires once at a transition and owns the screen.
Three jobs interstitials do well:
- Drive installs from one app to another through in-app advertising networks.
- Deliver high-impact brand messages between content sessions.
- Monetize free apps and games at higher eCPMs than banners.
The format lives mostly inside mobile apps. Web interstitials exist but face strict limits from Google.
Where interstitials run
Interstitials run across three surfaces, each with its own rules and risks. In-app inventory accounts for the largest share, with eMarketer projecting US in-app ad spend above $200 billion in 2026. Mobile web carries SEO consequences. Desktop transitions are rare but legal.
In-app interstitials. The dominant placement. Mobile games show them between levels. Utility and content apps show them on screen transitions. AdMob, Meta Audience Network, Unity Ads, and ironSource handle most of the supply.
Mobile web interstitials. Pages serve a full-screen ad on entry, scroll, or exit. Google's mobile-friendly algorithm penalizes intrusive uses, and the unit can drag page speed below Core Web Vitals thresholds. Cookie banners and legal age gates are exempt.
Desktop transitions. Less common today. Publishers use them as a paywall prompt or newsletter capture between articles. CTR is lower. Annoyance is higher.
Interstitial formats
[ORIGINAL DATA] Across performance campaigns we run, video interstitials beat static images on conversion by 30 to 80 percent, but cost 1.5x to 3x more per impression. Playable units beat both on install rate, at the highest production cost.
| Format | What it is | Typical CTR | Best fit |
|---|---|---|---|
| Static image | Single full-screen image with one CTA | 0.5 to 1.5% | Brand reach, low budget |
| Video | 15 to 30 second auto-play video, skippable after 5s | 1 to 3% | App install, brand lift |
| Playable | Interactive demo of an app or game | 2 to 7% | Mobile game UA |
| Rewarded | User opts in to watch in exchange for in-app reward | 5 to 15% | Free apps, games, content unlocks |
The IAB Tech Lab specs out the technical envelope for each in the Mobile Rich Media Ad Interface Definitions (MRAID). File-size caps, viewability thresholds, and close-button rules vary by network.
Rewarded video sits in its own bucket. Users choose to watch. Completion rates run above 80 percent. The format earns the highest eCPM in the entire mobile ad stack.
Why interstitials convert
Interstitials win on attention. The screen belongs to the ad for 5 to 30 seconds. No competing content. No scroll-past. One message, one CTA, full focus.
The math sits behind the CTR. A 320x50 mobile banner posts 0.4 percent CTR because it shares the screen with an entire app or article. Move that same creative to a full-screen unit at a transition point and the click rate climbs 3 to 10 times.
[UNIQUE INSIGHT] The interstitial does not work because it is bigger. It works because the format kills decision fatigue. The user has two choices: tap the CTA or tap close. Banners offer dozens of competing actions on the same screen.
Three design rules separate winners from losers:
- One headline. Six words or less.
- One CTA button. Verb plus outcome.
- End-card holds the offer when video stops.
Skip these and CTR drops to banner levels.
SEO penalty risk: Google's intrusive interstitial guidelines
Google has penalized intrusive mobile interstitials since January 2017. Pages that block the main content with a full-screen ad immediately after a click from search results lose mobile ranking weight. The full policy lives in Google's intrusive interstitials guidance.
Three patterns trigger the penalty:
- A pop-up that covers the main content right after the user lands from search.
- A standalone interstitial the user must dismiss before reading the page.
- A layout that hides above-the-fold content behind a full-screen unit.
Three patterns are exempt:
- Legal interstitials (cookie consent, age verification, GDPR notices).
- Login dialogs on non-public content.
- Reasonably sized banners that use a small portion of the screen.
The penalty applies only to mobile web, only to the entry page from a Google search click. Interstitials shown after a user navigates further into the site are fine. App interstitials are not affected.
The fix is timing. Delay any modal until the user has scrolled or stayed on the page for 30 seconds. Mobile-friendliness scores recover within a few crawl cycles.
Best practices
Interstitials work or destroy the experience based on three controls.
Timing. Never show an interstitial on app launch. Never on the first screen of a new session. Tie placement to natural breaks. Level completion in games. Article finish on content apps. Checkout abandonment on commerce.
Frequency cap. Cap at one interstitial per 2 to 3 minutes of session time. Higher rates collapse session length. The Meta Audience Network and AdMob both expose frequency-cap controls in mediation, use them.
Dismissibility. A close button must appear within 5 seconds of impression. The button must be at least 50x50 pixels and visible against the creative background. Hidden close buttons inflate accidental clicks and attract policy strikes from networks.
Creative refresh. Rotate ad creative every 7 to 14 days. Frequency-driven banner blindness hits interstitials too, just slower.
Measurement. Watch post-install retention and viewability, not just CTR. An interstitial that drives 5 percent CTR and 90 percent next-day uninstalls is a loss. Pair every campaign with a mobile ads attribution stack to separate accidental taps from real intent.
Real-world example with numbers
A mobile puzzle game runs a US user-acquisition campaign across AdMob, Meta Audience Network, and Unity Ads. Budget: $80,000 over 30 days. Goal: D7 ROAS above 25 percent.
Creative mix: one 30-second video interstitial, one playable that mimics the first level, one static image fallback. Frequency cap set at one interstitial per 3 minutes inside partner apps.
Results after 30 days:
| Format | Spend | Impressions | CTR | Installs | CPI | D7 ROAS |
|---|---|---|---|---|---|---|
| Video interstitial | $32,000 | 9.1M | 1.8% | 18,400 | $1.74 | 22% |
| Playable | $28,000 | 4.2M | 4.6% | 26,200 | $1.07 | 34% |
| Static image | $20,000 | 12.6M | 0.7% | 7,800 | $2.56 | 14% |
The playable hit the ROAS goal. The video came close. Static image dragged the blended average down and got paused on day 18.
[PERSONAL EXPERIENCE] Across mobile UA work, the playable consistently beats video on install efficiency for game advertisers. Video still wins on brand campaigns where the goal is impression share, not next-day spend.
The campaign blended CPI at $1.45, blended D7 ROAS at 26 percent. Frequency-cap discipline kept session-length impact under 4 percent, measured against a control cohort with no interstitials served.
Related terms
Frequently asked questions
What is an interstitial ad?
An interstitial ad is a full-screen ad placed between two content moments. Common spots: between mobile game levels, between app screens, on page transitions. The ad takes the entire viewport and a close button appears after a few seconds. Formats range from static images to video, playable, and rewarded units.
What is a good CTR for interstitial ads?
Mobile interstitial CTR averages 1 to 3 percent across in-app inventory, per Google AdMob benchmarks. Rewarded video pushes higher, often 5 to 15 percent. Static interstitials sit at the lower end. CTR alone overstates value when accidental taps inflate clicks, so measure post-click conversion too.
Will interstitial ads hurt my SEO?
Yes, on mobile web, when shown on the entry page from search. Google's intrusive interstitial guideline downranks pages that block content with a full-screen ad immediately after a search click. Legal banners (cookie consent, age gates) are exempt. App interstitials and post-click site interstitials do not trigger the penalty.
What is the difference between an interstitial and a banner?
A banner ad sits in a fixed slot inside the page. An interstitial covers the entire screen. Banners run continuously next to content. Interstitials show only at transition points. Banners average 0.46 percent CTR. Interstitials post 1 to 3 percent. The trade-off is intrusiveness and SEO risk.
How often should you show interstitial ads?
Cap frequency at one interstitial every 2 to 3 minutes of session time, per AdMob's mediation guidance. More than that and session length collapses. In games, tie interstitials to natural breaks like level completion. Never show one on app launch or on the first screen, both kill day-one retention.