Ad Auction

What is the ad auction?

The ad auction is the process Google uses to decide, for every single search query, which ads appear, in what order and at what price. It runs in fractions of a second, roughly around 200 milliseconds (an approximation, not a Google figure), and it runs again from scratch every time. There is no position you can buy permanently.

How the auction sorts

Google collects every ad that could match the search query and sorts them by Ad Rank. There is no public formula for it. According to Google's help center, six factors feed into it: your bid, the quality of your ads and landing page, Ad Rank thresholds, the competitiveness of the auction, the context of the search and the expected impact of assets. Google measures quality at auction time, for example through expected click-through rate, ad relevance and landing page experience. The Quality Score in your account, on the other hand, is per Google a diagnostic tool and not itself an input in the auction. Because the bid is only one of several factors, the highest bidder does not win automatically: a relevant ad with a matching landing page can overtake a considerably higher bid.

What you actually pay

Your maximum bid is a ceiling, not an invoice. You only pay as much as it takes to clear the thresholds and defend your place against the next bidder. That is why better ad and landing page quality works twice over: it can lift your position, and per Google it often leads to a lower click price you really pay. Quality Score works as the diagnostic that shows you where to start.

What you can influence in the auction

• Expected click-through rate: ads that pick up the search query word for word
• Ad relevance: clean separation by topic instead of one ad group for everything
• Landing page: fast, unambiguous and matching what the ad promised
• Bid control: Smart Bidding bids anew for every auction, but needs clean conversion tracking to do it

Pro tip: whoever only turns the bid dial buys the position expensively. From my practice, working on ad and landing page is the cheaper way up, because it improves position and price at the same time.

Further resources

• The Google Ads auction: who wins and who pays what
• Improving your Quality Score
• Auction Insights