What is an interstitial ad?
An interstitial ad is a full-screen ad shown at a natural transition point — between levels in a game, between articles, or during an app screen change. Because it takes the entire viewport and demands attention, it earns a much higher CPM than an inline banner — but that same intrusiveness is why Google and users penalize it when it’s used badly.
Interstitials exist on both web and in-app. On mobile web they’re tightly governed by Google’s intrusive-interstitial rules; in apps they’re a standard, high-value part of most mediation stacks.
What CPM do interstitials actually earn?
CPMs vary enormously by geography, platform, vertical, and demand — so treat any single number with caution. As a directional guide:
- App interstitials are typically among the highest-earning formats after rewarded video — often several times the eCPM of a standard banner in the same app.
- Tier-1 geos (US, UK, CA, AU) command materially higher CPMs than emerging markets — often by an order of magnitude.
- Gaming and utility apps tend to see the strongest interstitial demand, because the between-level break is a genuinely natural placement.
The important point for planning: a headline interstitial CPM means little without fill and frequency. A very high CPM shown too rarely — or capped by policy — can earn less total revenue than a lower-CPM format shown appropriately. This is why publishers judge interstitials on blended eCPM and revenue-per-session, not the sticker CPM. (See eCPM vs CPM for why.)
Why interstitials pay so well
Three things drive the premium:
- Full attention. The unit owns the screen, so viewability and completion are high.
- Strong creative canvas. Advertisers can run rich, full-screen creative, which they pay more for.
- Scarcity. Good interstitial inventory is limited by placement and frequency rules, so demand competes hard for it.
The risk: Google’s intrusive-interstitial policy
This is the part publishers underestimate. On mobile web, Google explicitly treats interstitials that block content as a negative ranking and experience signal. Interstitials that:
- appear immediately on page load,
- cover the main content the user came for, or
- are hard to dismiss,
can hurt both your rankings and your user retention. Legitimate exceptions exist (age gates, login, small banners, legal/cookie notices), but a promotional full-screen ad over your article is exactly what the policy targets.
In apps, the constraint is different — it’s less about SEO and more about store policies and user churn. Google’s own app guidelines discourage interstitials that show at app launch or interrupt an action the user is taking.
How to run interstitials safely
The format is a revenue win only with discipline:
- Place at natural breaks, never mid-task. Between levels, between articles, on a deliberate navigation event — not on load, not over content.
- Cap frequency. A per-user, per-session frequency cap protects the experience and keeps CPMs healthy (over-showing tanks both).
- Make dismissal obvious. A clear, immediate close control. Deceptive close buttons are a fast route to policy trouble.
- Watch Core Web Vitals on web. A full-screen unit can cause layout shift and input delay if it’s not handled cleanly. See Core Web Vitals & ad monetization.
- Compete the inventory. Route interstitial demand through header bidding / mediation so multiple buyers compete for that high-value slot, rather than handing it to a single network.
The bottom line
Interstitials are one of the highest-CPM formats available — but the CPM is only half the equation. Run them at natural breaks, cap them, keep dismissal honest, and compete the demand, and they’re a strong addition to a monetization stack. Run them aggressively and you’ll trade short-term CPM for lost rankings, churned users, and policy risk.
If you’re weighing interstitials for a site or app, the right move is to model them on blended eCPM and revenue-per-session with frequency caps applied — not the headline CPM. A yield optimization review, or a look at how app monetization mediation handles high-value formats, is the place to start.