Marketing metrics explained

Impression share in Google Ads: lost to budget, lost to rank

Impression share is the percentage of the impressions your ads actually received out of the impressions they were eligible to receive.

About the Google Ads connector

Search impression share is the same figure for the search network only. Where the rest went is reported as two separate figures, impression share lost to budget and impression share lost to rank, and the split between those two is the useful part.

How it's calculated

Impression share = impressions ÷ eligible impressions

The denominator is Google's estimate of how many impressions your ads could have received, based on your targeting settings, approval statuses and quality. Source: Google Ads Help, About impression share. The three figures add up:

Impression share + lost to budget + lost to rank = 100%

As an illustration with made-up numbers: a campaign was eligible for 20,000 impressions in a week and received 12,000. Its impression share is 60%. Of the 8,000 it missed, 5,000 were auctions it was not entered into because the daily budget had run out, which is 25% lost to budget, and 3,000 were auctions it entered and lost, which is 15% lost to rank.

What it tells you, and what it doesn't

Lost to budget means your ad was eligible and your campaign had no money left to bid. The fix is either more budget or a narrower campaign, cut to the keywords and hours that convert so the budget goes further.

Lost to rank means your ad entered the auction and placed too low to show. Ad rank is a combination of your bid and your quality, so the fix is a higher bid, a better quality score, or both. Spending more on the budget does nothing for this one, because the budget was not the limit.

What it does not tell you is whether the missing impressions were worth having. A campaign at 60% impression share might be showing for exactly the searches that convert and missing the ones that don't.

How to read it in your account

The impression share figures are columns you add to a campaign, ad group or keyword table, under the Competitive metrics group: Search impr. share, Search lost IS (budget) and Search lost IS (rank). Lost to budget is reported at campaign level only, because a budget belongs to a campaign. Search and display have separate versions, and search has further variants for the top of the page and the absolute top position (Search top IS, Search abs. top IS, and their lost-to-budget and lost-to-rank pairs), which are the same idea applied to a smaller set of positions. A share below 10% is shown as "< 10%" rather than as a figure. Source: Google Ads Help, Get impression share data.

Read it at the level where you will act, and read lost to budget and lost to rank side by side, because the same 40% gap calls for different fixes depending on which column it sits in.

Where it goes wrong

Chasing 100% is the expensive mistake. The last few points of impression share cost the most, because they are the auctions where you were outbid by someone who valued that click more. Buying them usually raises your average CPC faster than it raises conversions. Aim for the share a good CPC can buy.

A capped budget hides the rank problem. A campaign that runs out of money at lunchtime shows a large lost-to-budget figure and a small lost-to-rank figure, because it stopped entering auctions early. Lift the cap and the lost-to-rank figure often grows, because the campaign is now entering the afternoon's auctions and losing some of them.

Brand terms flatter the figure. They show almost every time because almost nobody else bids on them, so folding them into a campaign's figure makes a weak non-brand position look healthy.

Related metrics

Quality score: the quality half of ad rank, and the lever for lost to rank.

CPC formula: what the impressions you do win cost per click.

CTR formula: how many of the impressions you win turn into clicks.

Google Ads conversion tracking: whether the clicks were worth winning.

Keeping it current

A scheduled Fresh Sheets report can keep campaign figures from Google Ads in their own tab, with Search impression share, Impression share lost to budget and Impression share lost to rank as fields, so last week's figure is always there to compare against. The budget figure is offered at the account and campaign levels. A share Google reports as "< 10%" arrives as 9.99%, which is Google's floor rather than a measurement, so treat anything at 9.99% as "below 10%".

Fresh Sheets replaces that tab's contents on every refresh, so keep your formulas on a separate tab. This version finds the row by campaign name and the column by its heading, so it still works if a field is added and the columns move (replace Brand with your campaign's name):

=INDEX('Google Ads'!A:Z, MATCH("Brand", INDEX('Google Ads'!A:Z, 0, MATCH("Campaign name", 'Google Ads'!1:1, 0)), 0), MATCH("Search impression share", 'Google Ads'!1:1, 0))