The Math Behind How Google Ranks Ad

Mathematically, how you rank on Google Ad = Your Ad’s Quality Score x Ad’s Max Bid Per Click^[1]

What is Quality Score?

Quality Score is Google’s rating of the quality and relevance of both your keywords and PPC ads. Your Quality Score depends on multiple factors, including:

• Click-through rate (CTR)
• Landing page quality and relevance.
• The relevance of each keyword to its ad group
• The relevance of your ad itself

And the top ~7-8 ranked ads are positioned from 1-7. If your ad is ranked below that, Google won’t show it.

This is really interesting because if you have a high quality-score but bid at low $ CPC, you will beat your competitors who bid $$$ CPC but have low quality-score ads.

Let’s say Alex’s ad’s max bid is $4 and his quality score is 7. His ad rank score would be 21.

Let’s say we have a competitor, Bob, bidding at $10 but has a quality score of 2. His ad rank score would be 20.

21 > 20. Alex > Bob. Alex’s ad will show up above Bob’s ad even though he bided at less than half Bob’s bid.

^[1]It’s actually a little more complicated than that but I won’t go into the whole ad auction economics, that’ll take another 100 pages.