Picture this: you hang a poster in a crowded room, but most people never look in its direction. The message is there, perfectly printed, yet it goes unnoticed. Many publishers face the same problem in programmatic advertising when impressions are delivered but never genuinely viewed.
The scale of the issue is larger than many expect. Google’s Active View research found that 56% of display ads are never seen, even though they technically load on the page.
Publishers who want to compete in programmatic markets must understand what ad viewability is, why it influences demand, and how it shapes the value of every impression. Let’s break it down.
Table of contents
What is Ad Viewability?
Ad viewability represents the percentage of served impressions that had a real chance to be seen by a user.
The IAB viewability definition sets the baseline: for an ad to be considered viewed, at least 50% of the banner or creative must display on screen for more than one second. For video, the threshold is 50% in view for at least two seconds.
These standards matter because advertisers evaluate inventory quality through viewability. A low rate signals that ads load in positions users rarely reach or remain hidden due to layout or behavior.
Among the sites analyzed in industry studies, a direct correlation exists between effective CPM (eCPM) and ad viewability. Publishers with average viewability above 50% reportedly drew “significantly higher eCPMs (almost double)” compared to those with viewability below 50%.
Our data at Sevio also shows a clear pattern, where publishers with stronger ad viewability consistently benefit from higher CPMs, confirming the direct relationship between viewable inventory and demand strength.
Note that viewability is not the same as impressions.
An impression counts whenever an ad is served on a page, even if the user never scrolls far enough to see it. Ad viewability focuses only on the number of times an ad is displayed on the user’s screen and seen, meeting the IAB visibility threshold.
How Is Ad Viewability Measured?
Ad viewability is measured by verifying how many impressions met the IAB standard for being considered seen. Vendors track pixel visibility, time on screen, and whether the creative stayed inside the user’s viewport long enough to qualify.
Ad Viewability Formula:
Viewability rate = Viewable impressions / Measurable impressions × 100
Viewable impressions = Impressions that met the IAB rule of at least 50% of pixels in view for more than one second for display or two seconds for video.
Measurable impressions = Impressions your vendor could analyze for visibility. Not all served impressions fall into this bucket due to blockers or technical limitations.
Alongside the main formula, publishers often check supporting metrics like the ones below. These indicators help publishers by showing whether ads are not only viewable but also hold the user’s attention:
- Ad calls (ad requests) – Show how many chances an ad had to load during a user’s session. They reveal opportunity, not guaranteed visibility.
- Average viewable CPM – Cost per 1,000 impressions that were actually seen. A clearer pricing signal since it excludes non-viewable inventory.
- Active view – Google’s built-in measurement layer in Ad Manager, AdSense, and AdMob reports whether impressions were viewable.
- Burned budget – Amount spent on impressions that users never saw. A direct indicator of wasted spend.
- Measurable rate – Percentage of total impressions that were measurable. A quick gauge of how reliable your viewability data is.
- Viewable CTR – Click-through rate calculated only from viewable impressions. More accurate for judging real engagement.
- Viewability rate – Share of measurable impressions that counted as viewable according to IAB criteria.
- Viewable impression distribution – Shows how viewable impressions are spread across all impressions, measured or not. Useful when diagnosing uneven performance across placements.
Measurement partners use JavaScript tags or SDK-based tracking to detect:
- What percentage of the ad’s pixel area is visible within the viewport?
- How long does it stay in that position?
- Whether scroll behavior or layout shifts move the creative out of view?
The process relies on intersection ratios, viewport coordinates, render events, and scroll deltas. Some variation exists across vendors due to differences in sampling and browser APIs; however, the core reasoning remains consistent: confirm the pixel percentage and duration.
Ad Viewability Benchmarks and Standards (MRC, IAB)
As we presented at the beginning, ad viewability is defined and regulated through standards set by the Media Rating Council (MRC) and the Interactive Advertising Bureau (IAB), which serve as the industry’s reference point for what constitutes a viewable impression and how it must be measured. These standards aim to ensure that every reported viewable impression is backed by verifiable, client-side signals rather than assumptions or modeling.
According to the MRC, “a viewable impression must be based on strong, auditable measurement processes that reflect the ad’s actual opportunity to be seen.” Measurement vendors must detect the ad’s position in the viewport, confirm that the creative is fully rendered, and validate continuous exposure time.
The IAB adds that the environment must support reliable visibility tracking, stating that “only impressions measured in an environment capable of accurately indicating viewability should be classified as valid.” These principles ensure publishers and advertisers use comparable data across platforms and devices.
Benchmarks Publishers Typically Aim For
Industry benchmarks provide publishers with realistic targets. While results vary by placement, device type, and content structure, aggregated reporting across vendors generally points to ranges such as:
- Display: commonly 60% to 70%;
- Video: commonly 70% to 80%;
- High impact formats: often above 80%;
- Mobile apps: usually slightly higher than mobile web due to controlled rendering environments;
- Outstream video: typically 60% to 75%, strongly influenced by scroll behavior.
These ranges are frequently referenced in industry analyses, including reports from ad verification partners and SSP insights that show consistent patterns across markets.
Higher viewability typically results in stronger auction pressure and higher ad monetization. As agencies focus increasingly on “quality impressions,” inventory that surpasses these benchmarks attracts more competitive bids because it delivers more qualified exposure without increasing ad density.
Why Accreditation Matters
The IAB works with the Media Rating Council (MRC) to establish and enforce these standards, with the MRC accrediting measurement vendors.
Only MRC-accredited vendors can certify viewability. Companies undergo regular audits to confirm their measurement methods align with both MRC guidelines and IAB specifications.
This accreditation provides publishers and advertisers with a comparable data foundation, thereby reducing discrepancies between demand-side reporting and publisher-side reporting.
Format-Specific Standards Publishers Should Know
The MRC and IAB stress that viewability should reflect the user’s experience. Because of this, measurement rules differ by format:
- Large display creatives must meet higher pixel visibility standards compared to standard display formats.
- Video placements rely on continuous time-in-view detection rather than simple pixel coverage.
- Mobile environments require validation against OS-level restrictions that may block specific visibility signals.
These distinctions matter because publishers often benchmark formats against each other without considering that measurement rules vary.
Challenges for Measuring Viewability
Several technical and operational factors can distort results or limit the accuracy of measuring ad viewability. The most common challenges publishers face are:
- Ad blockers and privacy tools – Blocks measurement scripts, resulting in non-measurable impressions that shrink the data pool and lower accuracy.
- Lazy loading gone wrong – When triggers fire too late or too early, ads load outside real user attention zones, reducing viewability and inflating unviewed impressions.
- Layout shifts (CLS issues) – Ads load but get pushed out of the viewport after rendering, causing impressions that never become viewable.
- Slow page performance – Heavy pages delay ad rendering, so users scroll past placements before the creative loads.
- Cross-browser inconsistencies – Different browsers expose viewport data in slightly different ways, resulting in small but noticeable variations in reporting.
- Vendor measurement discrepancies – IAS, Moat, DoubleVerify, and others employ similar logic but differ in their sampling or thresholds, resulting in results that rarely match perfectly.
- Complex page structures – Infinite scroll, sticky elements, and dynamic content can confuse detection logic and hurt viewability scoring.
- Non-standard placements – Ads loaded in carousels, modals, or expandable units may be visible to users but not fully measurable by standard scripts.
- Mobile Web volatility – Fast scrolling and less predictable viewport changes create inconsistent exposure time, challenging vendors to track real visibility.
- Invalid traffic and spoofed views – Fraud schemes mimic impression delivery but cannot replicate real on-screen exposure, lowering measurable viewability and triggering discrepancies.
How to Improve Ad Viewability: Sevio’s Recommendations
To understand what truly moves the needle for publishers, we spoke with our ad operations experts whose experience is backed by years of development work on Sevio Ad Manager and by the long-term performance of Coinzilla, a project validated by both time and industry adoption.
Their insights align with trends reported across the ad adtech ecosystem and provide a clear roadmap for publishers seeking to measurably increase ad viewability.
1. Prioritize Placements That Users Naturally Reach
Ads integrated into content areas consistently outperform placements that rely on users scrolling to unexpected zones. Users tend to focus on article bodies, reference sections, and mid-content anchors. When ads appear in these spots, they stay in view longer and have a higher chance of meeting IAB’s pixel and time requirements.
Industry data reveals a strong correlation between placement quality and viewability. According to Pixalate’s Q1 2025 report, mobile app inventory achieved 67% viewability, while desktop web averaged ~59%, highlighting how environment and placement positioning impact exposure (mobile apps generally keep ads in stable, content-aligned zones, while desktop layouts often place units in areas users don’t always reach or see immediately).
2. Don’t Assume Above-The-Fold Guarantees the Highest Viewability
Above-the-fold units only work well when the page loads instantly. If heavy scripts delay rendering, users scroll before the creative appears, turning what should be a prime position into a weak performer. Slow load means the ad misses its exposure window.
Many publishers face this issue without realizing it. Global display viewability remains around 65%, according to industry tracking, despite a large share of these impressions being served above the fold.
This proves that “prime” placement doesn’t always translate into real visibility unless performance issues are fixed.
3. Fewer, Better Placements Often Outperform Pages Overloaded with Ads
More ads do not equal more revenue. When pages are packed with units, scripts compete for load priority, CLS increases, and viewability drops. Users also scroll past late-rendering banners before they appear.
Sevio’s experts repeatedly observe that publishers earn more by focusing on a limited set of strong placements rather than covering the page with ads.
Industry guidance supports this: adtech specialists recommend tightening layouts and reducing the total number of ad calls to improve consistency and viewability.
4. Refresh Only When the Ads are in the Viewport
Ad refresh can be a strong revenue driver, but only when it fires at the right moment. Refreshing an ad that sits outside the viewport inflates impression counts without increasing viewability. Sevio’s experts advise using conditional refresh triggers tied strictly to the ad being in view.
Best practices across the industry align with this approach, with multiple independent analyses highlighting that viewability depends on serving impressions during real on-screen exposure rather than relying on timed or blind refresh triggers.
A refresh fired at the wrong time is simply wasted budget and noise in reporting.
5. Use Sticky Formats to Increase Exposure Time
Sticky formats maintain visibility as users scroll, keeping ads within the viewport for far longer than standard inline units. A common example is a sticky sidebar banner: once a user reaches the sidebar and scrolls past its content, the sticky unit remains the last visible element. This stable presence drives longer exposure time and higher viewability.
Industry reporting shows that formats with extended exposure, such as sticky placements, regularly outperform traditional display units in viewability metrics.
Sticky positions are especially useful on long-form content, where scroll depth is high and inline banners quickly drop out of sight.
FAQ
Most publishers aim for 60–70% for display and 70–80% for video, with high-impact formats often performing above 80%. If your inventory consistently reaches or exceeds these ranges, it’s generally considered competitive in the market.
Check whether units with lower viewability also show weaker CPMs, reduced bid density, or lower fill. If higher-viewability placements on your site earn stronger CPMs, it’s a clear sign that poor viewability is limiting demand, pricing, or both.
Yes, ad viewability is a core KPI for both publishers and advertisers because it measures whether impressions had a real chance to be seen. It directly influences CPMs, campaign performance, and demand quality.
Yes, A/B testing is one of the most effective ways to increase viewability. You can compare placements, loading strategies, refresh logic, or sticky formats to see which variations deliver higher viewability and stronger monetization without harming user experience.
Final Thoughts
So, ad viewability stands at the center of programmatic performance. It shapes how advertisers judge quality, how auctions determine inventory pricing, and ultimately, how much revenue publishers earn.
Understanding how viewability works, measuring it accurately, and optimizing placements intentionally gives publishers a clear advantage in a competitive marketplace.
The strongest results come not from adding more ads, but from creating environments where impressions have a real chance to be seen.
When publishers treat viewability as a core KPI rather than an afterthought, every part of the monetization chain becomes more efficient, transparent, and sustainable.
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