Google Algorithm Fundamentals: How Ranking Works

Short answer

Google Search works in three stages, in its own words "and not all pages make it through each stage": crawling, where Google downloads pages it has found; indexing, where it analyzes them and stores the information; and serving, where "When a user searches on Google, Google returns information that's relevant to the user's query." Ranking happens in the last stage, and it isn't one algorithm but many systems. Google's ranking systems guide lists them, and its How Search Works page summarizes what they weigh: "the words of your query, relevance and usability of pages, expertise of sources, and your location and settings." Understanding ranking means understanding those inputs, and knowing which claims about them Google has actually made.

Sources

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The Pipeline

Stage	What happens	What can stop a page
Crawling	Google's crawlers download text, images and video from pages they find	Blocked by robots.txt, unreachable, never linked or listed
Indexing	Google analyzes the content and stores it in the index	Duplicate or canonicalized elsewhere, <!–INLINECODE0–>, low value, errors
Serving	Google returns the results it judges most relevant and highest quality	Less relevant or less useful than other pages for that query

Google’s in-depth guide adds a point worth keeping in mind: “Google doesn’t accept payment to rank pages higher, and ranking is done programmatically.” The first two stages are covered in how Google crawls and indexes websites.

What Ranking Weighs

How Search Works groups the inputs under five headings:

Meaning of your query: working out “the intent behind your query”, including spelling correction and synonyms.
Relevance of content: whether a page contains information relevant to the query; Google says “The most basic signal that information is relevant is when content contains the same keywords as your search query”. Google also says: “We also use aggregated and anonymized interaction data to assess whether search results are relevant to queries. We transform that data into signals that help our machine-learned systems better estimate relevance.”
Quality of content: signals that help determine which content “demonstrates expertise, authoritativeness, and trustworthiness”; see E-E-A-T explained.
Usability of content: “When all other signals are relatively equal, content that people will find more accessible may perform better.”
Context and settings: Google uses “information such as your location, past Search history, and Search settings”; the in-depth guide’s example is that “bicycle repair shops” shows different results in Paris than in Hong Kong.

Named Systems

From Google’s ranking systems guide:

System	Google's description
BERT	"allows us to understand how combinations of words express different meanings and intent"
RankBrain	"helps us understand how words are related to concepts"
Neural matching	understands "representations of concepts in queries and pages and match them to one another"
Passage ranking	identifies "individual sections or 'passages' of a web page" to judge relevance
MUM	"not currently used for general ranking in Search" but for specific applications
Link analysis and PageRank	how pages link to each other, part of core ranking
Reviews, freshness, original content, spam detection	systems for specific needs

The guide also lists retired systems. The helpful content system, “Announced in 2022 as the ‘Helpful Content Update’,” is one of them: “In March 2024, it evolved and became part of our core ranking systems”. Panda and Penguin are listed there too, as systems now part of others.

Page Experience: What Google Says

Two Google statements frame page experience. Its page experience documentation says: “There is no single signal.” It also says: “Core Web Vitals are used by our ranking systems.” And: “Beyond Core Web Vitals, other page experience aspects don’t directly help your website rank higher in search results.” How Search Works describes usability as a tiebreaker-like consideration. So HTTPS, mobile usability and the absence of intrusive interstitials are worth doing for users, while Core Web Vitals are the part Google says its ranking systems use. The metrics are in Core Web Vitals.

Links

Links still matter: PageRank is listed among Google’s core ranking systems, and How Search Works names, as one factor in quality, “understanding if other prominent websites link or refer to the content”. Links built to manipulate rankings fall under the link spam policy; see link building fundamentals.

Query Type Changes the Weighting

Google’s systems respond to what a query needs:

Freshness: freshness systems show fresher content for queries “where it would be expected”, such as a recently released movie.
Reliability for sensitive topics: reliable information systems “help surface more authoritative pages and demote low-quality content”.
Local intent: location shapes which results are relevant.
Results page features: the in-depth guide notes that the features on the page “change” with the query, local results for one search, image results for another.

Topics where mistakes can harm people get extra scrutiny in Google’s rater guidelines; see YMYL pages.

AI Features in Results

AI Overviews, which replaced Google’s Search Generative Experience, and AI Mode show AI-generated answers with links to sources. Google’s AI features documentation says there are “no additional requirements to appear in AI Overviews or AI Mode, nor other special optimizations necessary”, and that a supporting link must be indexed and eligible to show in Search with a snippet. Ranking fundamentals and AI visibility rest on the same pages. Measuring their effect is covered in AI Overviews.

Misconceptions

Claim	What Google says
"There's one algorithm with a fixed list of factors"	Google describes many systems and "hundreds of factors"
"Paying for ads helps rankings"	"Google doesn't accept payment to rank pages higher"
"Interaction data plays no role"	Google uses "aggregated and anonymized interaction data" to assess relevance
"HTTPS and mobile-friendliness are strong ranking boosts"	Beyond Core Web Vitals, page experience aspects "don't directly help" rankings
"There's still a separate helpful content update"	It became part of core ranking systems in March 2024

Applying It

Make pages crawlable and indexable before anything else.
Match the query’s intent in content and format.
Show expertise and trustworthiness through the content itself, who wrote it and what supports it.
Earn links and mentions rather than building them artificially.
Meet Core Web Vitals and keep pages usable.
Watch what the results page shows for your queries, since features change what ranking means. Ranking changes over time are covered in SERP volatility.

When a claim about a ranking factor reaches you, look for the Google statement behind it, as in the table above; a factor no Google document names is a hypothesis to test on your own pages, not a rule to build on.