Percentage of impressions your ads received out of total eligible impressions on Google Search Network (actual impressions ÷ eligible impressions × 100).
What is Search Impression Share? Search Impression Share: % of eligible Search impressions received (actual ÷ eligible × 100). Benchmarks: 60-90% healthy, 95%+ for branded keywords, 70-85% for high-converters. Formula: IS + Lost IS (Budget) + Lost IS (Rank) = 100%. Lost IS shows why you missed impressions. Measures market coverage. Don't chase 100% (unprofitable), optimize by keyword type and profitability.
Search Impression Share measures the percentage of Search Network impressions your ads received compared to the total number of impressions your ads were eligible to receive based on targeting settings, budget, and ad rank. Formula: (Actual Impressions ÷ Eligible Impressions) × 100. If your keyword was eligible to show 1,000 times but actually showed 600 times, your Search Impression Share is 60%. The missing 40% is split between Search Lost IS (Budget)—impressions lost due to insufficient daily budget—and Search Lost IS (Rank)—impressions lost due to poor Ad Rank. These three metrics always sum to 100%: Impression Share + Lost IS (Budget) + Lost IS (Rank) = 100%. Available at campaign, ad group, and keyword levels. Updated within 1-2 days. Industry benchmarks: 60-90% healthy overall, 90%+ for branded keywords, 70-80% for high-converting non-branded keywords.
Official Source: Definition verified from Google Ads Help Center (Last verified: January 2026)
"Impression share (IS) is the percentage of impressions that your ads receive compared to the total number of impressions that your ads could get. Impression share = impressions / total eligible impressions."
A personal injury law firm runs branded Search campaign targeting "[Firm Name]" keywords. Currently achieving 68% Search Impression Share, meaning they're missing 32% of searches for their own brand name. Concerned competitors are capturing their branded traffic.
Current Performance:
- Keyword: "[Law Firm Name]" (exact match)
- Monthly search volume: 1,200 searches
- Search Impression Share: 68%
- Search Lost IS (Budget): 8%
- Search Lost IS (Rank): 24%
- Total: 68% + 8% + 24% = 100% ✓
Current Results:
- Impressions: 816 (68% of 1,200)
- Missed impressions: 384 (32% of 1,200)
- Lost to budget: 96 impressions (8%)
- Lost to rank: 288 impressions (24%)
- Clicks: 490 (60% CTR)
- CPC: $4.20
- Cost: $2,058
- Conversions: 42 consultations
- CVR: 8.6%
- CPA: $49
Problem Diagnosis:
24% Lost IS (Rank) means poor Ad Rank (low bids or low Quality Score) is primary issue, not budget.
Solution:
1. Increase bids: $4.20 → $7.50 (+79%) to dominate branded auctions
2. Improve Ad Copy: Added firm differentiators ("30+ Years Experience," "No Fee Unless We Win")
3. Optimize Landing Page: Created branded landing page (firm history, attorney bios, client testimonials)
Results after fixes (30 days later):
- Search Impression Share: 68% → 96% (+28pp, captured most missed impressions)
- Search Lost IS (Budget): 8% → 2% (minimal budget constraints)
- Search Lost IS (Rank): 24% → 2% (fixed rank issue)
- Impressions: 816 → 1,152 (+41%)
- Clicks: 490 → 736 (+50%)
- CPC: $4.20 → $6.80 (+62%, expected for higher bids)
- Cost: $2,058 → $5,005 (+143%, more traffic at higher CPC)
- Conversions: 42 → 66 (+57%)
- CVR: 8.6% → 9.0% (better ad relevance)
- CPA: $49 → $76 (+55%, higher cost but capturing branded traffic worth it)
ROI Analysis:
Incremental 24 consultations/month × 15% close rate × $12,000 avg case value = $43,200 incremental monthly revenue
Incremental cost: $2,947/month
ROI: 1,367% (every $1 spent capturing branded IS generates $13.67 revenue)
Key insight: For branded keywords, high impression share (95%+) is non-negotiable even if CPA increases. Competitors appearing on your branded searches steal clients who were specifically looking for you. Missing 32% of branded searches meant losing 24 consultations/month worth $43K in revenue to capture 68% impression share that generated $49K. Capturing the missing 28pp generated $43K incremental revenue at $76 CPA (profitable for $12K case value).Search Impression Share reveals untapped market opportunity—80% impression share means you're missing 20% of potential customers searching for your offerings. For branded keywords, low impression share (<90%) is critical: competitors are appearing when customers search your brand name, potentially stealing traffic. A law firm with 65% branded impression share is losing 35% of searches for their firm name to competitors, costing qualified leads. Search Impression Share also diagnoses growth constraints: high Lost IS (Budget) means increasing budget will capture more traffic, while high Lost IS (Rank) means improving Quality Score or raising bids is needed. This guides investment decisions: if Lost IS (Budget) is 30%, increasing budget 40% can capture that missing traffic; if Lost IS (Rank) is 30%, more budget won't help—need better ads/landing pages. However, chasing 100% impression share is often unprofitable—capturing final 10% (90% → 100%) typically requires 2-3x higher CPCs as you compete for low-quality traffic hours (3am searches). Optimal impression share balances coverage and efficiency.
Chasing 100% impression share regardless of profitability—final 10-20% of impression share requires exponentially higher bids, often capturing low-intent searches at 2-3x normal CPA. Optimal is 70-85% for non-branded, 95%+ for branded only.
Confusing impression share with ad position—high impression share doesn't mean top positions. You can have 90% impression share but appear in 4th position consistently. Check "Impr. (Top) %" and "Impr. (Abs. Top) %" separately.
Not monitoring Lost IS (Budget) vs Lost IS (Rank) separately—seeing 40% total lost impression share without checking breakdown misses the solution. Lost IS (Budget) = add budget, Lost IS (Rank) = improve ads/bids. Different fixes.
Set different impression share targets by keyword type: Branded keywords (company name, product names): target 95%+ impression share to block competitors. Non-branded high-converters: target 70-85% to balance coverage and efficiency. Discovery/experimental keywords: target 40-60%, focus on learning over coverage. Segment and optimize accordingly.
Use impression share to size budget opportunities: If campaign has 25% Lost IS (Budget), increasing budget 35% can capture that traffic (assuming CPCs remain stable). Calculate revenue opportunity: Current conversions × (Lost IS % ÷ Current IS %) × avg conversion value = potential revenue.
Monitor impression share monthly, not daily—small daily fluctuations (67% Monday, 71% Tuesday) are normal due to auction dynamics. Monthly trending (75% January, 68% February, 61% March) signals issue—new competitors, seasonal changes, or budget constraints.
Combine impression share with profitability metrics—high impression share (85%) with poor ROAS (1.2x) means you're wasting coverage on unprofitable traffic. Reduce bids, accept lower impression share, improve profitability. Coverage without profit is meaningless.
Percentage of Search impressions lost because your daily budget was too low to show ads for all eligible searches.
Percentage of Search impressions lost because your Ad Rank was too low to show ads in auctions (due to low bids or poor Quality Score).
The percentage of impressions your ads received out of the total impressions they were eligible to receive.
A score that determines your ad position and whether your ad shows at all, calculated using bid amount, Quality Score, and other auction-time factors.
The average amount you're willing to spend on a campaign each day over the course of a month.
Search Impression Share targets vary by keyword type and business goals: Branded keywords (company name, product names): Target 95-100% impression share. These are users searching specifically for YOU—missing branded impressions means competitors are stealing your customers. Accept higher CPCs to dominate branded auctions. Example: Personal injury law firm should capture 98%+ of "[Firm Name]" searches. Missing 20% of branded searches likely loses more revenue than the CPC savings. High-value, proven converters (non-branded keywords with CVR >10%, strong ROAS): Target 70-85% impression share. High enough to capture most qualified traffic, low enough to avoid exponentially expensive marginal impressions. Example: "emergency plumber" keyword converting at 12% might target 80% IS to balance coverage and profitability. Core non-branded keywords (moderate converters, CVR 3-7%): Target 60-75% impression share. Healthy coverage without overpaying for low-intent searches (3am weekend searches often convert poorly). Example: "CRM software" keyword converting at 5% might target 65% IS, focusing budget on high-performing hours/geos. Experimental/discovery keywords (testing new terms, unclear intent): Target 30-50% impression share initially. Gather performance data before investing heavily. If keyword proves profitable, gradually increase IS target. Example: "sales automation platform" (new test keyword) starts at 35% IS to learn before scaling. Low-margin products/services: Accept lower impression share (50-65%) to maintain profitability. Missing some traffic is better than unprofitable coverage. Example: Drop-shipping low-margin products ($5 profit margin) can't afford expensive IS battles—settle for 55% IS with strict CPA targets. Competitive markets: In hyper-competitive industries (legal, insurance, finance), even 60% IS might be aspirational due to budget constraints. Focus on ROAS over coverage. General benchmark: Healthy campaigns typically achieve 60-90% overall Search IS. Below 50% suggests severe budget/rank constraints limiting reach. Above 90% risks overpaying for marginal impressions unless it's branded traffic.
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