Ad Rank is the score Google assigns to each ad in an auction; the highest Ad Rank wins the top position, the next-highest the second, and so on. It's not just bid — Google factors in Quality Score, expected impact of ad extensions, the auction context (device, time, location), and whether the ad meets the threshold for the position at all.
Ad Rank ≈ Bid × Quality Score × Extension Impact × Context Factors
Why it matters
Knowing Ad Rank is what lets you stop thinking about Google Ads as 'whoever bids highest wins'. A €1 bid with QS 9 will routinely beat a €3 bid with QS 4 on the same keyword. The cheapest path to top position is usually a higher Quality Score, not a higher bid.
Operator note
Use ad extensions liberally — sitelinks, callouts, structured snippets all feed extension impact. Each one adds a small lift to Ad Rank for free. Ignoring extensions is leaving money on the table.