Introduction
Google Ads campaigns are becoming more complex every year. Budgets get allocated, keywords are chosen and conversions roll in, yet campaigns can still leave money on the table when ads are not shown as often as they could be. That’s where Search impression share comes in. This set of metrics, sometimes dismissed as vanity data, tells you how often your ads appear relative to how often they were eligible to appear.
Knowing your impression share — and understanding what affects it — helps identify missed opportunities, diagnose why reach is limited and decide whether raising bids, improving ad quality or increasing budgets will actually help. With Google’s AI Overviews pushing organic and paid results further down the page, maximizing your share of visibility has never been more critical.
This guide expands on the definitions of Search Impression Share and its related metrics and provides actionable strategies.
The Competition for Visibility: Why Search Impression Share Matters
Search Impression Share (IS) is the percentage of impressions your ads actually received compared with the estimated number of impressions they were eligible to receive.
Eligible impressions depend on factors like audience targeting, quality score, bid and budget, and are estimated by Google for each auction.
High impression share tells you that your ads are appearing frequently relative to opportunities, while low impression share suggests your ads are missing out on exposure.
Agencies sometimes treat IS as a diagnostic rather than a performance metric because it doesn’t directly reflect clicks or conversions; however, in a world where AI‑generated search results reduce the number of opportunities for traditional ads, visibility becomes a precursor to every conversion.
These ranges can serve as starting points, but your ideal benchmark depends on your industry, budget and competition.
Search Impression Share (SIS) – The Total Area
Search Impression Share (SIS) measures the percentage of search impressions you received compared with the number you were eligible for. The formula is:
Search Impression Share = Impressions / Eligible Impressions
This metric includes ad impressions from anywhere on the SERP – top, middle, bottom.
If your SIS is 100%, your ads appeared every time they were eligible.
In reality, SIS is usually lower because of budget limitations, low bids, or poor ad quality.
Broad match keywords create large pools of eligible impressions, making it difficult to achieve a high SIS; conversely, phrase and exact match keywords create smaller eligible pools and typically have higher SIS because there are fewer opportunities to miss.
Understanding how match types and targeting choices expand or contract the eligible pool helps explain why your share may be high or low.
What’s a good SIS?
There is no one‑size‑fits‑all answer. The ideal SIS depends on your industry, keywords, budget and competition.
A few examples: For branded campaigns, a good Search Impression Share is considered to be at least 80%.
For brands with significant market share and awareness, non-branded SIS can range between 30% and 50%.
If you’re a small brand in a large market, your SIS might be limited by your budget – here we might be talking of even 15% as a starting point.
As mentioned earlier, high use of broad match keywords will also pull down SIS.
Note: A high Search Impression Share isn’t necessarily good. At some point, the bids and CPA/ROAS are no longer profitable – that’s when your bids are too high.
Your goal as a Google media buyer is to maximize visibility in a profitable manner.
Top Impression Share (Top IS)
Top Impression Share measures how often your ads appear in the top positions on the search results page. It focuses only on impressions that occurred above the organic results.
Google defines this metric as the ratio of top‑of‑page impressions to the number of impressions you were eligible to receive in the top positions.
Its formula is:
Top Impression Share (Top IS) = Impressions on top / Top Eligible Impressions
This metric is a prominence metric rather than an average position. It tells you how often your ad appeared anywhere in the top section above the organic results, when there were opportunities to do so.
A high Top IS indicates that your ads are consistently appearing above the organic results. Lower numbers signal that competitors are outbidding you or have better quality scores, pushing your ads below the organic listings.
Showing above organic results has become more important since the roll out of AI Overviews.
Absolute Top Impression Share (Abs. Top IS)
Absolute Top Impression Share measures how often your ads appear in the very first ad position — the absolute top of the search results. Google defines it as the ratio of impressions in the absolute top position to the number of impressions you were eligible to receive in that position.
The formula is:
Absolute Top Impression Share (Abs. Top IS) = Impressions in absolute top / Abs. Top Eligible Impressions
Because there is only one absolute top slot, this metric tends to be lower than Top IS. It is particularly important in highly competitive industries where the first result captures the majority of clicks.
Achieving a high Abs. Top IS requires a strong ad rank, which depends on bid, quality score and the expected impact of ad assets (formerly ‘extensions’).
| Metric | Formula |
| Search Impression Share (SIS) | Impressions ÷ Eligible Impressions |
| Top Impression Share (Top IS) | Top impressions ÷ Top‑eligible impressions |
| Absolute Top Impression Share (Abs. Top IS) | Abs. top impressions ÷ Abs. top‑eligible impressions |
| Search Lost IS (Rank) | Percentage of eligible impressions lost due to low ad rank |
| Search Lost IS (Budget) | Percentage of eligible impressions lost due to limited budget |
The Two Enemies of Visibility: Search Lost Impression Share
In order to improve ad visibility, it’s important to understand why you lost impressions. Google provides two complementary metrics:
- Search Lost Impression Share (Rank) — the percentage of eligible impressions you missed due to low ad rank.
Ad rank is determined by your bid, quality score (expected CTR, ad relevance and landing‑page experience) and the expected impact of ad extensions.
A search lost IS (rank) above 90 % means you lost most of your opportunities because other advertisers out‑ranked you.
- Search Lost Impression Share (Budget) — the percentage of eligible impressions you missed because your budget was too low.
If your daily budget runs out early, your ads stop serving, no matter how high your rank.
These metrics help diagnose whether you need to focus on bids and quality (rank) or allocate more budget and narrow targeting (budget).
High loss percentages warn that you may be competing in auctions you can’t afford or that your ads are not compelling enough.
Strategies to Improve Search Impression Share
Once you understand where your visibility gaps lie, you can take concrete steps to improve impression share and its related metrics.
- Increase Campaign Budgets
If you’re losing impressions due to budget, increasing your daily budget is the simplest fix.
Using the budget simulator, you can estimate how higher budgets could deliver more impressions.
Keep an eye on your efficiency KPIs – ROAS or Cost/Conv. – so you don’t overspend for incremental visibility.
- Raise Bids and Enhance Quality Score
Search lost IS due to rank means your bids or ad quality aren’t competitive. Raising bids improves your chance of winning auctions, but bidding alone isn’t enough.
Quality Score — based on expected CTR, ad relevance and landing‑page experience — heavily influences ad rank.
Improve CTR by writing compelling, keyword‑rich ad copy (use dynamic keyword insertion) and adding relevant sitelinks, callouts and other extensions; ensure that keywords, ads and landing pages align; and optimize landing pages for speed and mobile friendliness.
Higher Quality Scores reduce your cost per click while boosting your rank.
- Refine Your Keyword List
Cutting low‑performing keywords and focusing on high‑intent terms reduces wasted spend and increases your share on keywords that matter.
Refining your keyword list to core transactional terms narrows your eligible impression pool and improves SIS. Pause keywords with high cost and low conversion, and shift budgets to the best performers.
Consider adjusting match types: moving from broad to phrase or exact match reduces irrelevant impressions and improves quality scores.
- Reallocate Budget and Use Bid Automation Wisely
When budgets are tight, reallocate spend from underperforming campaigns or keywords to best performers.
Automated bidding strategies like Target CPA or Target ROAS can help maintain competitiveness across auctions without manually adjusting bids.
However, you may still need to raise your campaign budgets or adjust CPA targets to win more auctions when impression share is low.
Continuously monitor performance and adjust automation targets to balance costs and visibility.
The Era of AI Overviews: A New Competitor for Attention
Google’s AI Overviews (formerly known as Search Generative Experience) have dramatically altered the search landscape. Studies show that AI Overviews appear in roughly 55% of searches, up 115% since March 2025, and they are more likely to appear for informational queries than transactional ones. On desktop, AI Overviews occupy about 42% of screen space, and on mobile they can take up 48%.
Research summarised by Search Engine Land found that when AI Overviews appear, both organic and paid results are pushed down, leading to fewer clicks and a 25% loss in ad visibility.
Seer Interactive’s data (reported via DataSlayer) paints an even more alarming picture: between June 2024 and September 2025, paid CTRs on queries with AI Overviews fell 68% from 19.7% to 6.34%, while organic CTRs dropped 65%.
AI Overviews also shift consumer behavior: many users now seek answers directly in generative models or social platforms, bypassing search results entirely. Traditional metrics like rankings and CTRs no longer tell the full story.
How AI Overviews Affect Impression Share
AI Overviews reduce the number of visible ad slots and push them farther down the page, which inherently lowers impression share.
This means advertisers must pay more attention to Top IS and Abs. Top IS so that their ads appear above AI Overviews whenever possible.
Monitoring search terms that trigger AI Overviews allows you to shift budgets to queries with better visibility.
Action Plans: Maintain Visibility Despite AI Overviews
- Prioritize Top and Absolute Top – Aim for high Top IS and Abs. Top IS so your ads appear above or near AI Overviews. Use bid adjustments and strong ad copy to secure these premium positions.
- Optimize for Long‑Tail and Transactional Queries – AI Overviews are more prevalent for informational queries and appear less often for transactional keywords. Refine your keyword targeting to focus on purchase‑intent phrases where ads can still dominate.
- Increase budgets if possible – but track impact on profitability metrics in and outside of Google Ads.
- Optimize your landing pages – matching content to main keywords will improve quality score and reduce CPCs, thus improving SIS. By improving conversion rate and increasing AOV you’ll have more room to increase budgets and grow.
Conclusion
Search Impression Share and its related metrics are not vanity numbers; they’re diagnostic tools that reveal where and why your ads may be losing visibility.
By tracking SIS, Top IS and Abs. Top IS and understanding lost share due to rank and budget, you can prioritize high‑value keywords, refine targeting and make data‑driven decisions about bids and budgets.
In a competitive environment reshaped by AI Overviews – which cut available ad slots and reduce click‑through rates – improving your impression share on priority queries is one of the few levers you control.
Further Reading
- New On Google Ads: Headline and Description Assets
- Mastering A/B Testing in Google Ads: Strategies for Optimal Results
- Can YouTube Ads Drive Ecommerce Sales?
- 8 Ways to Scale Performance Max Campaigns For ECommerce
- Examples of Using ChatGPT for Google Ads
- Demand Gen: Google Ads Version of Paid Social Campaigns?
