Google Algorithm
Google’s algorithm is a set of automated ranking systems, not one formula; Google names the systems but publishes no list of factors or weights.
Reviewed by Alexander Yarovenko · Updated: 2026-10-04
Google’s search algorithm is not one formula but a set of automated ranking systems that look at many factors and signals about hundreds of billions of pages to return the most relevant, useful results in a fraction of a second. Some systems are core, such as PageRank and RankBrain; others serve specific needs, such as freshness or spam detection. Google publishes no list of ranking factors and no weights.
What it is and where the boundary lies
Google’s ranking systems work mainly at the level of the individual page, using a variety of signals to understand how to rank it. Site-wide signals and classifiers also contribute, but they do not decide everything: good site-wide signals do not guarantee that all content from a site ranks well, and poor ones do not mean all of it ranks badly. Google improves the systems through testing and gives notice of updates when that is useful to creators. The word “algorithm” in SEO therefore covers the whole stack: understanding language, matching pages, filtering duplicates and spam, and adjusting for freshness.
The main systems named by Google
| System | What Google says it does | What it means for you |
|---|---|---|
| BERT, neural matching, RankBrain, passage ranking | understand how words express meaning and intent, match concepts in queries and pages, and judge relevance of passages | write for the task behind the query; exact wording is not the only route to a match |
| Link analysis and PageRank | understand how pages link to each other; PageRank is still part of the core ranking systems, evolved since launch | links remain a signal, but no percentage or formula is published |
| Freshness | “query deserves freshness” systems show fresher content where it would be expected | freshness matters for some queries, not all |
| Deduplication, original content | show only the most relevant of very similar results; show original reporting ahead of those who merely cite it | copies and rewrites do not add value |
| Reviews, reliable information | reward high quality reviews; surface more authoritative pages and demote low-quality content | depth, original research and credible authors help |
| Site diversity | generally no more than two listings from the same site in top results | two similar pages from one site may compete |
| Spam detection (SpamBrain) | deal with content and behavior that violate spam policies | manipulation is filtered, not rewarded (spam policies) |
Google also lists systems it has retired as separate names. The helpful content system became part of the core ranking systems in March 2024, Panda was announced in 2011 and joined the core in 2015, Penguin was announced in 2012 and joined in 2016, and Hummingbird was a 2013 improvement. MUM, according to the same guide, is not currently used for general ranking.
Core updates
Several times a year Google makes significant, broad changes to its systems, called core updates. They do not target specific sites or individual pages, and most sites do not need to worry about them. Google announces them in the list of ranking updates; the Search Status Dashboard shows start and end dates (core update, Google’s guide to core updates).
How to use this knowledge
- When traffic changes, first check the Search Status Dashboard for an update whose dates match, and use the Google Updates tool to overlay update dates on your traffic.
- Rule out other causes: a security or spam issue, seasonality, a technical fault or a reporting glitch (debugging traffic drops).
- Compare equal periods in Search Console, for example the week after an update ends with the week before it began, by page type and by query group.
- Read the pages that lost the most against the question the query asks, not against the name of an old update.
- Improve content meaningfully rather than making quick fixes, and give changes time to take effect.
Practical example
A guide section loses clicks on dates that match a core update. The analyst waits for the update to finish, then compares clicks and impressions for the week after with the week before, split into guides, tools and glossary pages. Only the guides fell. The next step is to read those guides against the queries they were meant to answer and decide what to rewrite; pages that did not fall are left alone.
Common mistakes
- Quoting a number of signals: Google says “many factors and signals” and publishes no count or weights; any figure is someone’s estimate.
- Diagnosing by old names: Panda and Penguin are part of the core ranking systems and are not run as separate updates you can “be hit by”; look at the pages, not the name.
- Treating one site-wide fix as the cure: systems work at page level, so improve the weakest pages, not just the template.
- Deleting content at once: Google calls deletion a last resort; improve or restructure first.
- Waiting only for the “next core update”: improvements can take effect within days or take months, and smaller, unannounced core updates also happen.
- Repeating that an algorithm part is “the third most important signal”: the current guide makes no such ranking of systems.
How to validate the result
Write down the update dates and your own change dates in one log. After an update completes, compare equal-length periods in Search Console for the same page groups and note which groups changed. After you improve pages, wait several weeks before judging and compare against groups you did not touch. Treat a change that matches an update date as a hypothesis until the other causes are excluded.
More questions
Is there an official list of ranking factors?
No. Google describes its ranking systems and best practices but publishes no complete list of factors or weights.
How many ranking signals does Google use?
Google does not give a number; it says its systems look at many factors and signals. Figures such as “200 signals” are not in its documentation.
Is Panda still running?
Google lists Panda among retired systems: it became part of the core ranking systems in 2015 and is no longer a separate update.
Next practical step
Read the lesson on core updates for a full procedure, and overlay update dates on your traffic with the Google Updates tool.
Related concepts
- Core update — the broad changes announced several times a year.
- PageRank — the link analysis system that is still part of the core.
- RankBrain — the system that relates words to concepts.
- Helpful content system — now part of the core ranking systems.
- Google penalty — manual actions and spam demotions, which differ from algorithm updates.