Quality Score is Google's grade for how good your ad is at matching what users want. It's measured per keyword, on a 1–10 scale. Higher Quality Score = lower CPC for the same ad position. This is the single biggest cost-control lever in Google Ads, and most advertisers ignore it.
How it changes what you pay
Google's auction formula is roughly:
Ad Rank = Max CPC × Quality Score (+ other factors)
Two advertisers want the top spot. Advertiser A bids $5 with Quality Score 4. Advertiser B bids $3 with Quality Score 8. Their Ad Ranks are 20 and 24 — Advertiser B wins the spot for less money.
Roughly: a Quality Score 10 keyword pays about 50% less per click than a Quality Score 5 keyword for the same ad position.
The three components
1. Expected CTR
Google's prediction of how often your ad will be clicked when shown. Based on your historical CTR for that keyword, weighted by ad position. Above average = good. Below average = your ad copy or keyword choice is mismatched.
2. Ad Relevance
How closely your ad copy matches the search query. If you bid on "emergency plumber" but your ad headline is about "drain cleaning," ad relevance is below average — even if the user might still convert.
3. Landing Page Experience
How relevant, useful, and fast the page you send people to is. Includes:
- Does the page mention what they searched for?
- Page load speed (mobile especially)
- Mobile-friendly design
- Easy navigation, no deceptive content
Each component is graded "Below average / Average / Above average." All three above average = Quality Score 7-10. One below average = QS drops to 4-6 fast.
How to lift each component
Lifting Expected CTR
- Pause the bottom-CTR ad in each ad group; write a new variation.
- Use the keyword in the headline. Literally — "Emergency Plumber San Antonio" if that's the keyword.
- Add ad extensions / assets (sitelinks, callouts) — they raise CTR and indirectly lift Quality Score.
- Tighten match types — broad match drags CTR.
Lifting Ad Relevance
- Split big ad groups into smaller themed ones. One ad group per ~5-10 closely related keywords. Each ad group gets ads written specifically for those keywords.
- If "drain cleaning" and "water heater repair" are in the same ad group, separate them.
Lifting Landing Page Experience
- Send each ad group to its own landing page (or a unique section of a page) that mentions the keyword phrase.
- Get mobile speed under 3 seconds. PageSpeed Insights mobile score above 70.
- No interstitials, no aggressive popups before the user has read anything.
- Make the CTA visible above the fold on mobile.
The myths
- "Quality Score is a vanity metric." Wrong. It directly affects CPC.
- "You need Quality Score 10 to be competitive." Wrong. 7+ is fine. The jump from 4 to 7 is huge; from 7 to 10 is small.
- "Pause low-Quality-Score keywords." Often wrong. A keyword at QS 5 with profitable conversions is a keeper. Don't optimize for the score; optimize for the outcome.
What about Meta and other platforms?
Meta has "Relevance Score" / "Quality Ranking" — same concept, different name. Microsoft Ads has its own Quality Score too. The principles transfer: relevant copy + good landing page + healthy CTR = lower costs.