What Is Impression Share?
Impression share (IS) is one of the most diagnostic metrics in Google Ads. It tells you what fraction of the total possible auctions for your targeted keywords your ads actually entered and won a placement in. The formula is straightforward: your impressions divided by eligible impressions, multiplied by 100. If your ads were eligible to appear 10,000 times and were shown 6,500 times, your impression share is 65 percent.
Google reports three related impression share metrics. Search impression share applies to Search campaigns and shows how often your ads appeared on the Search Network. Display impression share applies to Display campaigns. Absolute top impression share shows the percentage of time your ad appeared in the very first position above the organic results. Each gives a different view of your market presence.
Two "lost IS" metrics explain why you missed the remaining impressions. Search IS lost (budget) means your ads were eligible but your daily budget was exhausted before all auctions could run. Search IS lost (rank) means your ad rank was too low to win the auction, usually because your bid or Quality Score was insufficient. Diagnosing which of these is responsible for low impression share tells you exactly where to focus your optimisation efforts.
For competitive South African markets such as legal services, financial products, and home improvement, impression share is a critical indicator of whether you are keeping pace with rivals. If a competitor consistently outbids you and achieves higher impression share on your brand terms, prospective customers who search your company name may see a competitor's ad before finding your own.
Impression Share In Practice
Consider a Sandton-based financial planning firm running Google Search ads for keywords like "financial advisor Johannesburg" and "retirement planning South Africa". If their search impression share sits at 35 percent, they are missing 65 percent of potential customer interactions. The IS lost (budget) column shows 20 percent and IS lost (rank) shows 45 percent. The correct response is not simply to increase budget. Addressing the Quality Score problems first by improving ad relevance, landing page experience, and expected click-through rate will raise ad rank and capture the rank-lost impressions without increasing spend.
Once Quality Score is optimised, a modest budget increase can then address the budget-limited portion. This sequential approach is far more efficient than simply throwing more rand at the campaign. South African advertisers who understand impression share decomposition consistently outperform those who optimise blindly, because they are solving the right problem at each stage of campaign maturity.
How impression share works
Impression share is a paid-search metric: the impressions your ads actually received divided by the total they were eligible to receive, as a percentage. An impression share of 65% means your ad appeared in roughly two of every three auctions it could have entered; the missing third was lost. Google reports where that lost share went, to budget, when spending limits stopped your ads showing, or to rank, when your ad rank was too low to qualify. This makes impression share a diagnostic of missed opportunity: it shows not just how visible you are but why you are not more visible, which points directly at whether the constraint is money or ad quality and bidding.
How to improve impression share
How you improve impression share depends on why it is low, which Google's lost-impression-share metrics tell you. If share is lost to budget, your ads stop showing once the daily budget runs out, so raising or reallocating budget, or tightening targeting so spend goes further, lifts it. If share is lost to rank, your ad rank is too low to qualify for some auctions, so improving Quality Score through relevance and better landing pages, or raising bids, helps. Often the smarter fix is improving relevance rather than simply spending more, since a higher Quality Score wins more auctions at lower cost. Chasing a very high impression share is not always wise, though, since the last few points can be disproportionately expensive.
FAQ
What impression share should I aim for in Google Ads?
For brand keywords, aim for an impression share above 90 percent so competitors cannot consistently appear above you for your own name. For non-brand keywords, 60 to 80 percent is a realistic target for most South African campaigns. Chasing 100 percent on all keywords is rarely cost-effective and often indicates overbidding.
What causes low impression share?
Low impression share is caused by two things: insufficient budget, which means Google stops showing your ads once your daily cap is hit, or a low ad rank, which means your bids or quality scores are too low to win auctions. Google reports these as impression share lost to budget and impression share lost to rank separately in your campaign data.
What impression share should you aim for?
There is no universal target. High impression share suits brand terms or campaigns where you want maximum visibility, but chasing the last few points elsewhere can be disproportionately expensive. Aim for a share that balances visibility against efficient cost per conversion, guided by the goal of the campaign.