Banners Are Not Dead: Why This Format Still Matters
Banner ads are the oldest format in mobile advertising, and every few years someone declares them dead. Yet banners continue to generate billions in revenue for app publishers worldwide. The reason is simple: banners deliver consistent, predictable revenue with minimal user experience disruption. They will never match interstitial or rewarded video eCPMs on a per-impression basis, but their always-on nature means they accumulate meaningful revenue across long sessions.
The difference between a banner implementation that earns $0.30 eCPM and one that earns $2.50 eCPM comes down to size selection, placement strategy, refresh rate tuning, and viewability optimization. This guide covers all four.
Banner Sizes: Choosing the Right Dimensions
Not all banner sizes perform equally. The size you choose affects eCPM, advertiser demand depth, and user experience in fundamentally different ways.
320x50 Standard Banner
The smallest and most common mobile banner size. It occupies minimal screen real estate, making it the least intrusive option. eCPMs are the lowest of any banner size, typically ranging from $0.15 to $0.80 in Tier 1 markets. However, because it is so small, you can display it persistently without meaningfully impacting gameplay or app usage. Best suited for apps where screen space is at a premium.
320x100 Large Banner
Double the height of the standard banner. This size offers a meaningful eCPM uplift of 30 to 60 percent over 320x50 while still being relatively unobtrusive. It provides advertisers more creative space, which improves click-through rates and makes them willing to pay more. This is an excellent default choice for most apps.
300x250 Medium Rectangle (MREC)
The highest-performing banner size by eCPM, often delivering two to four times what a standard banner earns. The 300x250 MREC commands premium demand because it is large enough for rich creative formats including video. However, it takes up significant screen space, so it works best as an inline placement within scrollable content rather than a persistent overlay.
Adaptive Banners
Google's adaptive banner format dynamically adjusts width to fill the available screen width while optimizing height for the device. Adaptive banners typically outperform fixed-size banners by 15 to 25 percent in eCPM because they maximize the creative canvas for each device. If your ad SDK supports adaptive banners, use them as your default unless you have a specific reason not to.
Placement Strategies That Maximize Revenue
Where you place the banner within your app's UI matters as much as which size you choose. Placement affects viewability, which directly drives eCPM.
Bottom-Anchored Persistent Banner
The most common placement. A banner fixed to the bottom of the screen that remains visible throughout the user's session. This works well for games and utility apps where the primary interaction happens in the center and top of the screen. Ensure the banner does not overlap interactive elements or system navigation bars.
Top-Anchored Banner
Less common but effective in certain app layouts, particularly content-reading apps or tools where the user's primary focus is the center of the screen. Top placement can actually yield slightly higher viewability in some apps because users' eyes naturally start at the top when opening a new screen.
Inline Between Content
For apps with scrollable content feeds, news readers, or level-select screens, placing a 300x250 MREC between content items is highly effective. These placements achieve strong viewability because the user actively scrolls past them, and the larger format commands premium eCPMs. Space them at least every 3 to 4 content items to avoid a cluttered feel.
In-Feed Native-Style
Some ad networks offer native banner templates that match the look and feel of surrounding content. These perform exceptionally well in list-based UIs because they feel less like advertising. eCPMs for native-style banners can be 40 to 80 percent higher than standard display banners of the same size.
Refresh Rates: The Hidden Revenue Lever
Banner refresh rate determines how often a new ad is loaded into an existing banner placement. This is one of the most impactful yet least understood optimization levers available to publishers.
The Tradeoff
Faster refresh means more impressions per session, which seems like it should mean more revenue. But it does not work that way in practice. Advertisers track viewability and engagement metrics. A banner that refreshes every 15 seconds generates many impressions, but each impression has very low viewability scores and near-zero click-through rates. Advertisers respond by bidding less, so eCPM drops.
Optimal Refresh Intervals
- 30 seconds: The minimum refresh interval allowed by most ad networks including Google. This is aggressive and should only be used for high-engagement placements where the banner is consistently in view.
- 45 seconds: A balanced choice for most apps. It generates healthy impression volume while maintaining respectable viewability metrics.
- 60 seconds: Conservative but delivers the highest per-impression eCPMs. Best for placements where viewability may be inconsistent, such as screens the user might navigate away from quickly.
Important: Never set refresh rates below 30 seconds. Google Ad Manager and AdMob will reject impressions or flag policy violations for refresh intervals under 30 seconds. Other networks have similar minimums.
Smart Refresh
The most sophisticated approach is event-based refresh rather than time-based. Refresh the banner when the user takes a meaningful action, such as completing a level, switching tabs, or scrolling to a new content section. This ensures each new impression coincides with active engagement, which lifts both viewability and eCPM.
Viewability: The Metric That Drives Everything
Viewability measures whether an ad was actually seen by the user. The IAB standard defines a viewable display impression as one where at least 50 percent of the ad's pixels are in view for at least one continuous second.
Why Viewability Matters for eCPM
Advertisers increasingly buy on viewable CPM (vCPM) rather than standard CPM. This means they only pay for impressions that meet the viewability threshold. If your banner has 40 percent viewability, you are effectively wasting 60 percent of your ad calls. Improving viewability from 40 percent to 70 percent can double your effective revenue even if raw eCPM stays flat.
How to Improve Banner Viewability
- Keep banners on screen. Anchored placements (top or bottom) inherently have higher viewability than inline placements that scroll off screen.
- Pause refresh when not visible. If the user navigates to a different screen or the app goes to background, stop refreshing. Impressions served while the banner is not visible count against your viewability score.
- Avoid placing banners below the fold on screens where the user may not scroll down far enough to see them.
- Test placement positions with viewability as the primary metric, not just click-through rate or eCPM.
Sticky vs Inline: Making the Right Choice
Sticky banners remain fixed on screen regardless of scrolling. Inline banners are embedded within the content and scroll with it.
- Sticky banners deliver higher total impression volume and more consistent viewability. They are the right choice for games and single-screen utilities.
- Inline banners allow you to use larger formats like 300x250 MREC without permanently sacrificing screen space. They are the right choice for content-driven apps with scrollable feeds.
Many successful publishers use both simultaneously: a sticky 320x50 or adaptive banner at the bottom, plus inline 300x250 MRECs within content feeds. As long as the two placements are not visible at the same time, this does not violate ad network policies and effectively doubles your banner revenue.
Combating Banner Blindness
Banner blindness occurs when users mentally tune out banner ads after repeated exposure. It reduces click-through rates, which eventually reduces eCPMs as advertisers measure diminishing engagement.
- Vary creative formats. Use mediation to rotate between different ad networks, each of which serves different creative styles.
- Use animation-capable formats. Rich media and video banners (especially in MREC size) break through blindness better than static images.
- Refresh strategically. Event-based refresh keeps the creative fresh and relevant to the user's current context.
- Rotate placements. If your app has multiple screens, vary which screens show banners and which do not. Occasional absence makes the presence less ignorable.
Combining Banners With Other Ad Formats
Banners work best as the steady revenue baseline complemented by higher-impact formats. A well-balanced monetization mix might include persistent banners for consistent per-session revenue, interstitials at natural breaks for high-eCPM spikes, and rewarded video for user-initiated premium placements.
When running banners alongside interstitials, hide the banner during full-screen ad display. Overlapping ads violate most network policies and create a cluttered experience. Your ad SDK or mediation platform should handle this automatically, but verify it in testing.
With RevenueFlex managing your Google Ad Manager waterfall, every banner impression competes across all your demand sources to ensure the highest possible bid wins. Combined with the placement and refresh strategies in this guide, you can turn the humble banner into a reliable and significant revenue stream for your app.