Interstitial Ads: Best Practices That Don't Drive Players Away

Interstitial ads are one of the highest-CPM display formats available to web gaming publishers (rewarded video aside). They are also the fastest way to damage your player retention if you get the implementation wrong.

The basic trade is simple: interstitials typically earn $8–15 CPMs on gaming traffic, roughly 2–4× what a standard 300×250 or 728×90 unit earns (illustrative US ranges from our experience; your rates depend on geography, format and season). But a player who is interrupted too often stops coming back. The difference between a well-implemented interstitial strategy and a bad one is not subtle. It is the difference between your best-performing ad unit and the reason players leave your site.

Here is how to get the revenue without the damage.

The Core Tension: CPM vs. Retention

Every interstitial impression is a gamble. You are betting that the revenue from this single impression is worth more than the risk of losing this player's future sessions.

At a $12 CPM, each interstitial impression earns you about $0.012. Now take a returning player who visits 20 times a month and sees 8–12 ad impressions per visit: that is 160–240 impressions a month. At a blended $4–8 CPM across all formats, that player is worth roughly $0.60–1.90 a month, every month they keep playing. Lose that player to interstitial frustration, and you have traded about a cent for a recurring revenue stream.

This math is why frequency and timing matter more than any other factor in interstitial monetization.

Frequency Rules

The table below is an illustrative model, not measured data. It shows the shape of the trade-off we see across the gaming sites we work with: each step up in frequency adds less revenue and costs more retention. Your own numbers will differ, which is why the testing section later in this post matters.

The sweet spot for most gaming sites is one interstitial every 3–5 levels or rounds. That captures most of the revenue an interstitial can add while keeping the retention cost small. Going more aggressive than one per two rounds usually crosses into territory where the retention loss outweighs the CPM gains.

The 90-Second Rule

Regardless of level/round frequency, never show an interstitial less than 90 seconds after the previous one. This catches edge cases where players move through short levels quickly. A player completing five 15-second puzzle levels in 75 seconds should not see two interstitials in that span.

Implement this as a hard minimum timer alongside your level-count frequency cap. The timer takes priority.

Session-Level Caps

Beyond per-interval frequency, set a session-level maximum. These are starting points to test against, not fixed rules:

• Sessions under 5 minutes: Maximum 1 interstitial
• Sessions 5–15 minutes: Maximum 2–3 interstitials
• Sessions 15–30 minutes: Maximum 4–5 interstitials
• Sessions 30+ minutes: Maximum 6–7 interstitials

These caps prevent your most engaged players, the ones generating the most total ad revenue, from being penalized for playing longer.

Timing Rules: When to Show, When to Never Show

Frequency is how often. Timing is when. Both matter equally.

Safe Interstitial Moments

These are moments where the player's attention is already transitioning. An interstitial here feels like a natural pause, not an interruption:

1. Level completion screens. The player just finished something and is in a brief reward state. This is the single best moment for an interstitial.
2. Game over / death screens. The player already stopped playing. An interstitial before the retry button adds a few seconds of delay but does not interrupt action.
3. Menu returns. When a player exits gameplay to return to a menu, they have already mentally disengaged from the game loop.
4. Loading screens. If your game has legitimate loading times (3+ seconds), an interstitial during the load replaces dead time rather than adding new time.

Timing That Will Cost You Players

These are moments where an interstitial is most likely to hurt retention:

1. During active gameplay. This should be obvious, but we still see it on sites we review. Never interrupt a player mid-action.
2. Immediately on page load. The player has not even started playing. A full-screen ad before the first game interaction is the timing most likely to make a new visitor leave, and on mobile it is a prestitial, which the Better Ads Standards flag (more below).
3. During tutorials or onboarding. New players are evaluating your site. An interstitial during their first experience signals that ads matter more than their enjoyment.
4. On pause. The player paused intentionally (phone call, checking another tab). Punishing them with an ad when they return feels adversarial.
5. After a purchase or reward claim. If a player just completed a rewarded ad or made a micro-transaction, hitting them with an interstitial immediately erases the positive feeling from that action.

Stay Inside the Better Ads Standards

The Coalition for Better Ads standards, which Chrome's built-in ad filtering enforces, list the full-screen experiences that users find most intrusive. For interstitials, the relevant ones are:

• Desktop: prestitial ads with a countdown (a full-page ad before content that makes the user wait).
• Mobile: prestitial ads (a full-screen ad before content loads, with or without a countdown) and postitial ads with a countdown (a full-screen ad after the user acts that forces them to wait before dismissing it).

A site that repeatedly fails these standards risks having Chrome filter all of its ads. In practice this means: never open a session with a full-screen ad on mobile, and do not force players to wait out a timer before they can close an interstitial.

The Close Button

Make the interstitial dismissible, and make the close control visible and usable from the start. On mobile in particular, a forced countdown before the close button appears is the "postitial with countdown" pattern the standards flag. If you serve video creatives inside the interstitial slot, the creative's own skip control handles the video; the slot itself should still be closable.

The close button must be clearly visible and reasonably sized. A tiny "X" in the corner that is hard to tap on mobile is functionally the same as no close button. Your players know it, and they resent it.

A/B Testing Interstitial Frequency

You should not trust industry averages alone. Your specific audience, game mix and traffic sources will shift the optimal frequency. Here is how to test it properly.

Test Design

1. Split traffic evenly between control (your current frequency) and variant (the new frequency you want to test).
2. Run for a minimum of 14 days. Retention effects take time to manifest. A 3-day test will show you CPM changes but miss the retention impact.
3. Track both RPM and 7-day/30-day return rate. RPM alone is misleading because it does not capture the cost of lost players.
4. Segment by traffic source. Organic search players and social media referral players have different ad tolerances. Test them separately if your traffic is mixed.

Key Metrics to Compare

• Revenue per user per 30 days (RPU30): The single most important metric. It combines RPM, session frequency and retention into one number.
• Bounce rate on interstitial pages: If a specific trigger point shows a much higher bounce rate than the rest of the site, that trigger point is too aggressive regardless of overall averages.
• Session depth after interstitial: How many more pages or levels does the player visit after seeing the interstitial? If players routinely leave right after one, the interstitial is acting as an exit signal.

What a Typical Test Looks Like

When publishers reduce interstitial frequency from aggressive to moderate, the pattern usually runs like this (direction, not a promise of size):

• Short term (week 1): RPM drops, because there are fewer high-CPM impressions.
• Medium term (weeks 2–4): Return rates and session depth start to improve.
• Long term (months 2–3): RPU30 often ends up at or above the aggressive setup, because more players stay and keep generating impressions.

The revenue recovered from better retention usually outweighs the per-session RPM drop, but not always. The exception is sites with very low return rates already: if players are not coming back regardless, per-session revenue matters more. That is exactly why you measure RPU30 rather than assume.

Implementation Checklist

Before your next interstitial deployment, verify these items:

• Frequency capped at 1 per 3–5 game levels/rounds
• Hard minimum 90 seconds between interstitials
• Session-level caps based on session duration
• Interstitials fire only at natural break points (level end, game over, menu return)
• No interstitials on first page load or during tutorials
• No forced countdown before the interstitial can be closed
• Close button is clearly visible and tappable (minimum 44×44 px tap target)
• A/B test running to validate your specific frequency
• Tracking RPU30 alongside RPM to catch retention effects

What to Do Next

Interstitials are not inherently hostile to players. They are hostile when implemented without discipline. The publishers earning the most from interstitials are not the ones showing the most of them; they are the ones showing them at the right moments, at a sustainable frequency, with an easy way out. If you want to see how other gaming publishers have approached their ad setups, see publisher results, or read our guide to RPM, eCPM and fill rate to set up the metrics your test will need.