What Is Quality Score in Google Ads?

Quality Score is a 1-10 diagnostic metric reported at the keyword level in Google Ads. It is not an auction input. Google states this directly: "Quality Score is not an input in the ad auction. It's a diagnostic tool to identify how ads that show for certain keywords affect the user experience." The number is a backward-looking estimate of how your ad and landing page performed relative to other advertisers on the same exact-match keyword over the prior 90 days.

Three component evaluations determine the score: expected clickthrough rate (eCTR), ad relevance, and landing page experience. Each is rated above average, average, or below average. SEISO's reverse-engineering of 15,000+ accounts — reported by Search Engine Land — found the formula follows a point sum: 1 base point + up to 3.5 for eCTR + up to 3.5 for landing page experience + up to 2.0 for ad relevance = 10 maximum. eCTR and landing page experience each carry ~39% of the formula weight; ad relevance carries ~22%.

Ad Rank — not Quality Score — determines where your ad appears and what you pay. Ad Rank is recalculated at auction time using real-time quality evaluations. The stored 1-10 QS number does not enter that calculation. The correct use of Quality Score is diagnostic: identify which component is below average, fix the structural cause, and watch auction-time performance improve. For how bid strategy interacts with Ad Rank, see Google Ads bidding strategies. For keyword-level QS baselines, see Google Ads keywords and match types.

Key Takeaways

• Quality Score is a diagnostic, not an auction input. Google confirms it explicitly. The stored 1-10 score does not enter the auction; the real-time component evaluations do.
• eCTR and landing page experience each carry ~39% of the QS formula weight — together ~78%. Ad relevance carries ~22%. Prioritize eCTR and LPE first.
• Ad Rank has six inputs, not two. Bid and quality are the two you control. Thresholds, competitiveness, search context, and asset impact shift with every query.
• Quality Score appears in the CPC denominator. QS 8 earns a ~37% CPC discount vs. QS 5 baseline; QS 4 carries a ~25% premium (practitioner estimates, Adalysis).
• In Smart Bidding accounts, visible QS loses predictive power — broad match queries fall outside the exact-match trailing window. Audit component ratings as a structural diagnostic, not a KPI.
• Ad Rank thresholds block low-quality ads regardless of bid. Low impression share despite an adequate bid signals a threshold block. The fix is quality, not a higher bid.

The Three Components of Quality Score

Quality Score's three components are each rated above average, average, or below average against other advertisers who showed ads for the exact same search query over the prior 90 days. The comparison uses exact-match performance only — broad match query expansions are not included in the trailing window, which is why broad match keywords frequently show lower visible QS even in well-structured accounts.

The SEISO formula: QS = 1 (base) + eCTR points (0-3.5) + LPE points (0-3.5) + ad relevance points (0-2.0). A keyword with all three components at Average scores 5-6 (1 + 1.75 + 1.75 + 1.0 = 5.5). All three above average yields the maximum of 10. The key finding: improving eCTR or LPE has twice the formula impact of improving ad relevance. Fix those two first on any below-average keyword.

Quality Score Is a Diagnostic, Not an Auction Input

Google describes Quality Score as a "warning light for a car's engine" — it signals that something needs attention, but it is not the engine. The 1-10 number is a trailing estimate based on 90-day exact-match comparison data. At auction time, Google evaluates ad quality in real time; that real-time signal feeds Ad Rank. The stored 1-10 score does not. Source: Google Ads Help, Using Quality Score to guide optimizations (2026).

The QS number tells you which component failed — not why. A QS 3 with eCTR below average and LPE below average flags two structural gaps; it does not identify whether the eCTR problem is weak ad copy or wrong keyword-to-ad match. The component rating directs the audit; the audit identifies the cause. Track Quality Score component changes alongside Google Ads metrics and KPIs to confirm that component improvements translate to actual CPA movement.

Expected Click-Through Rate: The Highest-Impact Component

Expected CTR (eCTR) is Google's prediction of how likely your ad is to be clicked when shown, compared to other ads for the same exact-match keyword. It carries ~39% of the QS formula weight — equal to landing page experience and twice ad relevance. eCTR is measured against the exact-match competition only, which is why broad match keywords often show below-average eCTR ratings even when the campaigns perform.

Ad group structure is the highest-leverage eCTR fix. A single ad group containing 30 keywords and one RSA produces mediocre eCTR because the ad cannot match the intent of 30 different queries. Splitting into clusters of 5-10 intent-matched keywords — each with RSA headlines targeting that specific query pattern — consistently moves eCTR component ratings from average to above average. MB Adv Agency has found this restructuring approach effective in legal PPC and home services accounts where generic structure dragged eCTR below average on the highest-spend keywords.

RSA Ad Strength is not Quality Score. A Weak Ad Strength score can coexist with an above average eCTR rating if the combinations that actually serve are well-matched to the competition. Track eCTR component status, not Ad Strength, as your quality signal. For how campaign type selection affects which ad formats drive eCTR signals, see the campaign types guide.

Ad Relevance and Landing Page Experience

Ad relevance and landing page experience together account for ~61% of Quality Score. Landing page experience carries the same ~39% estimated weight as eCTR — yet it is the most neglected component in accounts where campaign managers control ad copy but cannot modify landing pages.

Ad Relevance (~22% of QS)

A below-average ad relevance rating almost always traces to a single structural cause: too many semantically unrelated keywords in one ad group competing for one RSA. The fix is structural, not copy-level. Keyword insertion in headlines improves eCTR, not relevance. Ad relevance improves when the thematic intent of the entire ad group matches the query pattern. Source: Google Ads Help, About Quality Score.

Landing Page Experience (~39% of QS)

Google evaluates landing page experience on four dimensions: content relevance to the query, site transparency, ease of navigation, and mobile performance (Core Web Vitals). A keyword with LPE below average and eCTR above average signals that the ad is compelling but the page does not deliver — the bottleneck is the page, not the campaign.

MB Adv Agency has found that LPE consistently underperforms in accounts where a single site-wide homepage serves as the landing page for multiple keyword themes. Dedicated pages aligned to specific service queries — even simple, single-purpose pages — regularly lift LPE ratings from average to above average on the highest-spend keywords. This pattern holds across dental PPC, financial services PPC, and SaaS software PPC engagements where multi-service homepages were the default landing destination. The LPE improvement compounds: better landing page experience improves QS, lowers actual CPC, and — on the same page — improves conversion rate simultaneously.

What Is Ad Rank? The Six-Factor Model

Ad Rank is the score Google computes for every ad in every auction — recalculated fresh for every query and independently for every position on the page. It determines whether your ad shows, where it shows, and what you pay. The "Ad Rank = bid x Quality Score" simplification is years out of date. Google's current documentation lists six factors. Source: Google Ads Help, About Ad Rank (2026).

Two advertisers with identical bids and identical QS can have different Ad Ranks on the same query if one has active sitelinks and the other does not. Context signals shift Ad Rank even when nothing in the account changes. Position 1 cannot be locked through bid management alone because four of the six inputs are outside advertiser control. For how bidding strategies interact with the bid factor in Smart Bidding modes, see the bidding strategies guide.

Ad Rank thresholds: minimum quality floors that an ad must clear to show at any position on a given query. Google does not publish these thresholds. A keyword with very low impression share despite an adequate bid is almost certainly threshold-blocked — the fix is improving eCTR, ad relevance, or LPE signals, not raising bids. Source: Google Ads Help, Ad Rank thresholds: Definition. For roofing PPC and HVAC PPC accounts, seasonal demand spikes compound threshold issues — the fix is quality improvement, not seasonal bid escalation.

How Ad Rank Sets Your Actual CPC

Google's auction is a modified second-price system. You pay just enough to beat the Ad Rank of the advertiser immediately below you — rounded up to the nearest $0.01. Google states this directly: "you only pay what's minimally required to clear the Ad Rank thresholds and beat the Ad Rank of the competitor immediately below you." This mechanism is what makes Quality Score a cost-efficiency lever: QS appears in the denominator of the actual CPC calculation. Source: Google Ads Help, Actual cost-per-click (CPC): Definition (2026).

The practitioner-standard rendering of Google's described mechanism — not a formula Google publishes officially:

Actual CPC ≈ (Competitor Ad Rank immediately below you) ÷ (Your Quality Score) + $0.01

Advertiser B wins position 1 with a lower bid and pays $2.51 — well below the $4.00 max bid — because Quality Score (8) sits in the denominator. Advertiser A's $5.00 bid wins position 2 at comparable cost. Quality Score improvement affects both sides of the CPC equation: it influences Ad Rank (through real-time quality evaluation) and lowers actual CPC through the denominator effect. An advertiser who improves QS from 4 to 8 on a keyword they already win pays less and becomes harder to displace without a material bid increase from the competitor. For managed PPC engagements in competitive markets, see PPC management in Austin, TX and PPC management in Chicago, IL.

CPC Impact by Quality Score Level

The relationship between Quality Score and CPC is documented by Adalysis and Store Growers through practitioner reverse-engineering of Google's CPC formula structure. These are estimates — Google does not publish an official modifier table — but they are consistent across independent sources and reflect the structural relationship the actual-CPC formula implies.

How to Diagnose and Improve Quality Score

The diagnostic sequence starts with component ratings, not the 1-10 number. Open the keyword view in Google Ads, add the three QS component columns, and sort by spend descending. Below-average ratings on your highest-spend keywords are the only findings requiring immediate action.

• eCTR below average: Restructure the ad group to 5-10 tightly themed keywords. Rewrite RSA headlines to match intent cluster language. A/B test; pause low-CTR RSA variants. The 90-day comparison window means improvements take time to surface in the rating.
• Ad relevance below average: The ad group is too broad. Break into tighter intent clusters where every keyword maps to the same user goal. The fix is structural — not copy-level headline tweaks.
• LPE below average: Audit content relevance against the keyword and ad copy. Run PageSpeed Insights on mobile. Reduce interstitials. Consider a dedicated landing page if the current URL serves multiple intent clusters.

Prioritize by spend impact. A below-average LPE rating on a $9.87 CPC keyword costs more than the same rating on a $2.00 keyword. Fix in order of dollar exposure, not alphabetically by campaign. Source: Google Ads Help, Using Quality Score to guide optimizations.

Frequently Asked Questions

Methodology

Primary sources: Google Ads Help documentation verified Q2 2026 — About Quality Score, Using Quality Score to guide optimizations, About Ad Rank, Ad Rank thresholds, and Actual cost-per-click: Definition. QS formula weights: SEISO analysis of 15,000+ accounts via Search Engine Land. CPC modifier table: Adalysis; Store Growers (2026). Smart Bidding analysis: Optmyzr (2026). Industry benchmarks: WordStream 2026; WordStream 2025. Reviewed by MB Adv Agency, Q2 2026.