Interstitial Ad in Mobile Development: Essence, Types, and How It Works

What is Interstitial Ad?

Interstitial Ad is a full-screen ad format that completely covers the app interface during natural transitions between screens. Unlike banner ads that occupy only part of the screen, interstitial ads capture the user's full attention, leading to higher engagement.

The primary purpose of Interstitial Ad is to monetize pauses in the user flow: transitioning between game levels, opening a new app section, or completing an action. These moments are considered the least critical for user experience, making them ideal for displaying ads.

According to Statista (2025), interstitial ads generate on average up to 40% of revenue from all ad income in free-to-play games when frequency is properly configured.

Key Characteristics of Interstitial Ad

Interstitial ads differ from other formats in several ways. Full-screen coverage ensures 100% ad visibility — the user cannot ignore the ad as they can with banners. The ad is usually dismissed via a close button that appears 5-15 seconds after the ad is shown.

The creative size must match the device screen resolution. Android and iOS support all modern resolutions from 320×480 to 1242×2688 pixels. Adaptive creatives automatically scale to fit the screen, simplifying the ad material preparation process.

How Interstitial Ads Work

The lifecycle of an Interstitial Ad consists of three stages: preloading, display, and dismissal. Preloading happens in advance — the SDK loads the ad creative in the background so that when the right moment arrives, the ad can be shown instantly with no delay for the user.

After loading, the creative is stored in the SDK cache until the show() method is called. It is important to control the cached ad's lifespan — most SDKs invalidate the creative after 30-60 minutes from loading. Displaying an expired ad may cause an error or show a blank screen.

Interstitial Ad Loading Modes

There are two main approaches to loading interstitial ads. Pre-load — loading the ad in advance, right after SDK initialization. This mode provides instant display but requires managing the creative's lifecycle. On-demand — loading at the moment the app is ready to show the ad. The downside of this approach is the delay for the user while the creative loads.

Most developers use a hybrid approach: they preload the next ad immediately after the current one is closed. This way, by the time the next impression is due, the creative is already ready. AdMob recommends this strategy for achieving maximum fill rate.

class InterstitialManager(private val context: Context) {
    private var interstitialAd: InterstitialAd? = null
    private val adUnitId = "ca-app-pub-3940256099942544/1033173712"

    fun loadInterstitial() {
        val adRequest = AdRequest.Builder().build()
        InterstitialAd.load(context, adUnitId, adRequest,
            object : InterstitialAdLoadCallback() {
                override fun onAdLoaded(ad: InterstitialAd) {
                    interstitialAd = ad
                }
                override fun onAdFailedToLoad(error: LoadAdError) {
                    interstitialAd = null
                }
            })
    }

    fun showInterstitial(activity: Activity) {
        interstitialAd?.show(activity)
    }
}

Main Types of Interstitial Ad

Interstitial ads come in several formats, each suited for different types of apps and use cases. The choice of format directly affects eCPM and user experience.

Static Full-Screen Ads

The classic format — a static image or Rich Media displayed full-screen. These creatives have minimal weight (up to 500 KB) and load quickly even on weak connections. Static Interstitials are suitable for news apps, content feeds, and services where display speed is critical. The average eCPM for static interstitial ads is 4-8 USD.

Video Interstitials

Full-screen video ads lasting 15-30 seconds. This format delivers the highest eCPM among all interstitial ad types — up to 15-20 USD. Video Interstitials with cost-per-view (CPV) pricing generate maximum revenue in gaming apps, where users are accustomed to ad breaks between levels.

Playable Interstitials

An interactive format that lets users play a demo of the advertised game directly within the ad. Playable creatives occupy a special niche — they are hardly perceived as ads but rather as part of the gameplay. Playable Interstitials have the highest Conversion Rate (CVR) — up to 25-30%, but require significant creative production costs.

Pros and Cons of Interstitial Ad

Interstitial ads provide developers with a powerful monetization tool, but require a balanced approach to integration. Understanding the strengths and weaknesses of the format helps make informed decisions when developing a monetization strategy.

Advantages of Interstitial Ad

The full-screen format ensures maximum ad visibility — the user cannot ignore the ad until it is dismissed. High eCPM makes Interstitial Ad one of the most profitable formats: when configured correctly, it generates 3-5 times more revenue per impression than banner ads.

Additionally, interstitial ads support various creative formats: static, video, Rich Media, playable. This allows advertisers to create engaging ads and developers to earn premium rates for higher-quality inventory.

Disadvantages of Interstitial Ad

The main drawback is the negative impact on user experience. According to an Appsflyer study (2025), showing interstitial ads too frequently reduces user retention by 15-20% in the first week after install. Displaying at the wrong moment (e.g., during an active action) causes frustration and may lead to app uninstallation.

Another important drawback is ad blocking. Some users employ ad-blockers that can intercept requests to ad SDKs and block Interstitial Ad display, reducing fill rate and revenue predictability.

• Pros: high eCPM, full-screen coverage, support for various creative formats.
• Cons: risk of lower Retention, negative perception with frequent display, ad-blocker interference.
• Optimal balance: no more than 3-4 Interstitial impressions per day per user.

SDKs for Interstitial Ad

Choosing an ad SDK directly affects fill rate, eCPM, and display stability of interstitial ads. Several platforms are available on the market, each with its own integration features and monetization mechanics.

Google AdMob

The largest ad platform with access to the Google Display Network. AdMob offers simple integration through the Google Mobile Ads SDK and supports all Interstitial Ad types. Its main advantages are high fill rate (up to 95-99% in developed countries) and transparent revenue statistics. To get started, simply register your app in AdMob and obtain an Ad Unit ID.

Unity Ads

A platform optimized for gaming apps. Unity Ads offers advanced frequency capping and targeting settings, as well as support for video interstitial and playable creatives. In non-gaming apps, Unity Ads fill rate may be lower than AdMob, but in the gaming segment this platform often delivers higher eCPM.

AppLovin and ironSource

Both platforms provide in-app bidding, allowing you to maximize revenue through real-time auctions. AppLovin MAX is one of the most popular mediation platforms, combining multiple ad networks into a single system and automatically selecting the highest-bidding ad for each impression.

Integrating Interstitial Ad into Your App

The integration process for interstitial ads includes several stages: SDK initialization, ad loading, choosing the display moment, and handling dismissal. Each stage requires attention to detail for stable operation and maximum revenue.

SDK Initialization and Loading

The first step is initializing the ad SDK at app startup. For Google Mobile Ads SDK, this is done in the Application onCreate method. After initialization, you need to preload the Interstitial Ad — call load() at app start and immediately after the previous ad is dismissed.

import GoogleMobileAds

class AdManager: NSObject {
    private var interstitial: InterstitialAd?
    private let adUnitID = "ca-app-pub-3940256099942544/4411468910"

    func loadAd() {
        InterstitialAd.load(
            withAdUnitID: adUnitID,
            request: GADRequest()
        ) { [weak self] ad, error in
            if let error = error {
                print("Failed: \(error.localizedDescription)")
                return
            }
            self?.interstitial = ad
        }
    }

    func showAd(root: UIViewController) {
        interstitial?.present(fromRootViewController: root)
    }
}

Choosing the Display Moment

A critical aspect is determining the right moment to show the Interstitial Ad. Best display points include: completing a game level, transitioning between screens, exiting settings, opening new content. Display during active use (reading an article, filling out a form) is strongly discouraged — it irritates users and leads to rapid app uninstallation.

Check the loading state before display: do not show the ad if it has not loaded yet. Use SDK callbacks to track readiness and handle loading errors without displaying an empty or broken creative.

Handling Dismissal and Reloading

After the Interstitial Ad is dismissed, you should immediately start loading the next ad. This ensures that by the next display moment, the creative will be ready. The full cycle includes: display → handle dismissal → load new ad → ready for next display.

Interstitial Ad Performance Metrics

Monitoring key metrics of Interstitial Ad helps evaluate monetization effectiveness and adjust the display strategy in a timely manner. Key indicators include eCPM, fill rate, CTR, and impression RPM.

eCPM (Effective Cost Per Mille)

The basic metric showing revenue per thousand impressions. eCPM for Interstitial Ad varies by region, creative type, and season. The global average is 8-12 USD, while in Tier-1 countries (USA, UK, Canada) it reaches 20-35 USD.

You can increase eCPM by using in-app bidding and mediation — competitive auctions between ad networks ensure each impression is sold at the maximum price. AppLovin MAX and AdMob Mediation support real-time bidding.

Fill Rate

The percentage of successful ad loads out of total requests to the ad network. A fill rate of 95% or higher is considered good. Low fill rate means a significant portion of ad inventory is not monetized. Causes of low fill rate: limited advertiser budget, unsupported regions, incorrect Ad Unit configuration.

Retention Rate

The user retention metric after Interstitial Ad display. According to Adjust (2025), at a frequency of more than 5 impressions per day, Day-7 Retention drops by 25%. Optimal frequency — 3-4 impressions per day for non-gaming apps and up to 6-8 for games, where users are accustomed to ad breaks.

Interstitial Ad Best Practices

An effective strategy for using Interstitial Ad is built on a balance between monetization and user experience. Following best practices allows you to maximize revenue without significantly reducing Retention.

Frequency Capping

Set a limit on the number of Interstitial Ad impressions per user per day. The recommended value is 3-4 for general-purpose apps and 6-8 for games. AdMob allows you to configure frequency cap at the app level and set an interval between impressions — at least 60 seconds.

Display Timing

Show Interstitial Ad only at natural transition points. Use blocking flags to prevent display during active user actions. The rule of thumb: do not show ads within the first 30 seconds after app launch and within 30 seconds after the previous dismissal.

A/B Testing

Test different frequencies, timings, and creative types. Run an A/B test with two user groups: show one group Interstitial Ad every 60 seconds, the other every 120 seconds. Firebase A/B Testing allows you to run such experiments without publishing a new app version.

class AdFrequencyManager {
    private val minIntervalMs = 60000L
    private var lastShowTime = 0L

    fun canShowInterstitial(): Boolean {
        val now = System.currentTimeMillis()
        return (now - lastShowTime) >= minIntervalMs
    }

    fun onAdShown() {
        lastShowTime = System.currentTimeMillis()
    }
}