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Impression share (IS) measures the percentage of eligible impressions your ads actually received compared to the total impressions they were eligible to receive. It is one of the most diagnostic metrics in paid search and display advertising because it reveals not just how you're performing, but how much additional opportunity exists — and whether budget or quality is the limiting factor. Search impression share in Google Ads is calculated as: impressions received / estimated maximum impressions eligible. An impression share of 42% means you're showing for 42% of the searches where you could have appeared. The remaining 58% was lost — either due to budget (your daily budget ran out) or ad rank (your combination of bid and Quality Score wasn't high enough to win the auction for every eligible query). Google Ads segments Lost IS into two categories: Lost IS (Budget) — impressions lost because your budget ran out before the day ended — and Lost IS (Rank) — impressions lost because your Ad Rank wasn't high enough to win the auction at that query's competition level. This segmentation is essential for diagnosis: lost to budget means increasing your budget would capture more impressions; lost to rank means improving Quality Score or increasing bids would be more effective. Search top impression share measures what percentage of your impressions appeared at the top of the page (above organic results, in the premium positions 1–4). Absolute top impression share measures what percentage appeared in position 1 specifically. Target IS strategy sets specific IS goals for your campaigns, letting Google's automation adjust bids to achieve that share. Impression share goals should be calibrated by campaign type. Brand keyword campaigns should target 90–100% IS — you should dominate your own branded searches. High-converting non-brand terms should target 60–80% IS to balance coverage with profitability. Broad awareness keywords can operate at lower IS (30–50%) while maintaining positive ROI. The relationship between IS and ROI is non-linear — the incremental cost of capturing the last 10% of IS often exceeds the value it generates.
Impression Share (%) = Impressions Received / Total Eligible Impressions × 100 Where each variable represents a specific measurable quantity in the finance and lending domain. Substitute known values and solve for the unknown. For multi-step calculations, evaluate inner expressions first, then combine results using the standard order of operations.
- 1Gather the required input values: Actual ad impressions, Estimated maximum impressions, Percentage of eligible, Percentage of eligible.
- 2Apply the core formula: Impression Share (%) = Impressions Received / Total Eligible Impressions × 100.
- 3Compute intermediate values such as Lost IS (Budget) if applicable.
- 4Verify that all units are consistent before combining terms.
- 5Calculate the final result and review it for reasonableness.
- 6Check whether any special cases or boundary conditions apply to your inputs.
- 7Interpret the result in context and compare with reference values if available.
This example demonstrates a typical application of Impression Share Calc, showing how the input values are processed through the formula to produce the result.
This example demonstrates a typical application of Impression Share Calc, showing how the input values are processed through the formula to produce the result.
This example demonstrates a typical application of Impression Share Calc, showing how the input values are processed through the formula to produce the result.
This example demonstrates a typical application of Impression Share Calc, showing how the input values are processed through the formula to produce the result.
Professionals in finance and lending use Impression Share Calc as part of their standard analytical workflow to verify calculations, reduce arithmetic errors, and produce consistent results that can be documented, audited, and shared with colleagues, clients, or regulatory bodies for compliance purposes.
University professors and instructors incorporate Impression Share Calc into course materials, homework assignments, and exam preparation resources, allowing students to check manual calculations, build intuition about input-output relationships, and focus on conceptual understanding rather than arithmetic.
Consultants and advisors use Impression Share Calc to quickly model different scenarios during client meetings, enabling real-time exploration of what-if questions that would otherwise require returning to the office for detailed spreadsheet-based analysis and reporting.
Individual users rely on Impression Share Calc for personal planning decisions — comparing options, verifying quotes received from service providers, checking third-party calculations, and building confidence that the numbers behind an important decision have been computed correctly and consistently.
New campaigns: IS starts low and improves over 2–4 weeks as Quality Score
New campaigns: IS starts low and improves over 2–4 weeks as Quality Score builds from initial performance data In practice, this edge case requires careful consideration because standard assumptions may not hold. When encountering this scenario in impression share calculator calculations, practitioners should verify boundary conditions, check for division-by-zero risks, and consider whether the model's assumptions remain valid under these extreme conditions.
Seasonal IS compression: competitive auctions during peak seasons (Q4,
Seasonal IS compression: competitive auctions during peak seasons (Q4, back-to-school) reduce everyone's IS — budget increases needed to maintain coverage
Local campaigns: geo-targeted campaigns show IS for local area only; national
Local campaigns: geo-targeted campaigns show IS for local area only; national IS and local IS are measured separately In practice, this edge case requires careful consideration because standard assumptions may not hold. When encountering this scenario in impression share calculator calculations, practitioners should verify boundary conditions, check for division-by-zero risks, and consider whether the model's assumptions remain valid under these extreme conditions.
Smart campaigns: Google's Smart Campaigns don't show IS metrics — use Expert
Smart campaigns: Google's Smart Campaigns don't show IS metrics — use Expert Mode campaigns for IS visibility In practice, this edge case requires careful consideration because standard assumptions may not hold. When encountering this scenario in impression share calculator calculations, practitioners should verify boundary conditions, check for division-by-zero risks, and consider whether the model's assumptions remain valid under these extreme conditions.
| Keyword Type | Target IS | Typical Achievable IS | Primary IS Lever |
|---|---|---|---|
| Branded Keywords | 90–100% | 85–100% | Budget (keep funded) |
| High-converting Non-brand | 60–80% | 50–80% | Quality Score + Budget |
| Category / Informational | 30–60% | 25–60% | Bid strategy |
| Competitor Terms | 20–50% | 15–50% | Ad relevance + Bid |
| Long-tail Keywords | 50–80% | 40–85% | Quality Score (easier to win) |
In the context of Impression Share Calc, this depends on the specific inputs, assumptions, and goals of the user. The underlying formula provides a deterministic relationship between inputs and output, but real-world application requires interpreting the result within the broader context of finance and lending practice. Professionals typically cross-reference calculator output with industry benchmarks, historical data, and regulatory requirements. For the most reliable results, ensure inputs are sourced from verified data, understand which assumptions the formula makes, and consider running multiple scenarios to bracket the range of likely outcomes.
In the context of Impression Share Calc, this depends on the specific inputs, assumptions, and goals of the user. The underlying formula provides a deterministic relationship between inputs and output, but real-world application requires interpreting the result within the broader context of finance and lending practice. Professionals typically cross-reference calculator output with industry benchmarks, historical data, and regulatory requirements. For the most reliable results, ensure inputs are sourced from verified data, understand which assumptions the formula makes, and consider running multiple scenarios to bracket the range of likely outcomes.
In the context of Impression Share Calc, this depends on the specific inputs, assumptions, and goals of the user. The underlying formula provides a deterministic relationship between inputs and output, but real-world application requires interpreting the result within the broader context of finance and lending practice. Professionals typically cross-reference calculator output with industry benchmarks, historical data, and regulatory requirements. For the most reliable results, ensure inputs are sourced from verified data, understand which assumptions the formula makes, and consider running multiple scenarios to bracket the range of likely outcomes.
In the context of Impression Share Calc, this depends on the specific inputs, assumptions, and goals of the user. The underlying formula provides a deterministic relationship between inputs and output, but real-world application requires interpreting the result within the broader context of finance and lending practice. Professionals typically cross-reference calculator output with industry benchmarks, historical data, and regulatory requirements. For the most reliable results, ensure inputs are sourced from verified data, understand which assumptions the formula makes, and consider running multiple scenarios to bracket the range of likely outcomes.
In the context of Impression Share Calc, this depends on the specific inputs, assumptions, and goals of the user. The underlying formula provides a deterministic relationship between inputs and output, but real-world application requires interpreting the result within the broader context of finance and lending practice. Professionals typically cross-reference calculator output with industry benchmarks, historical data, and regulatory requirements. For the most reliable results, ensure inputs are sourced from verified data, understand which assumptions the formula makes, and consider running multiple scenarios to bracket the range of likely outcomes.
In the context of Impression Share Calc, this depends on the specific inputs, assumptions, and goals of the user. The underlying formula provides a deterministic relationship between inputs and output, but real-world application requires interpreting the result within the broader context of finance and lending practice. Professionals typically cross-reference calculator output with industry benchmarks, historical data, and regulatory requirements. For the most reliable results, ensure inputs are sourced from verified data, understand which assumptions the formula makes, and consider running multiple scenarios to bracket the range of likely outcomes.
In the context of Impression Share Calc, this depends on the specific inputs, assumptions, and goals of the user. The underlying formula provides a deterministic relationship between inputs and output, but real-world application requires interpreting the result within the broader context of finance and lending practice. Professionals typically cross-reference calculator output with industry benchmarks, historical data, and regulatory requirements. For the most reliable results, ensure inputs are sourced from verified data, understand which assumptions the formula makes, and consider running multiple scenarios to bracket the range of likely outcomes.
プロのヒント
Create a branded keyword campaign separate from non-brand campaigns and set an explicit IS target of 90%+ with a Target Impression Share automated bidding strategy. Losing branded impression share to competitors bidding on your brand name costs you high-intent searchers already familiar with your product — these are your highest-conversion prospects and the easiest impressions to profitably capture.
ご存知でしたか？
Google's ad auction runs approximately 8.5 billion times per day — each one a separate first-price sealed-bid auction completed in under 200 milliseconds. The concept of impression share was developed specifically to give advertisers visibility into how many of these auctions they're participating in vs. missing, transforming the auction from a black box into a measurable, optimizable process.
参考文献
- ›Google Ads Help: About Search Impression Share
- ›WordStream Impression Share Optimization Guide
- ›Search Engine Land: Impression Share Best Practices
- ›Optmyzr: Impression Share Analysis Methodology
- ›Google Ads Quality Score Impact Research