SEO Term Definition
RankBrain
RankBrain is Google's machine learning system that helps interpret search queries and match them to the most relevant results — especially for ambiguous or never-seen-before queries.
Reviewed by Alexander Yarovenko · Updated: 2026-06-25
What is RankBrain?
RankBrain is a machine learning algorithm deployed by Google in 2015 that helps process search queries and determine the most relevant results. Google confirmed it is one of the top three ranking signals (alongside content and links).
What RankBrain Does
- Interprets ambiguous queries — queries that could mean different things depending on context
- Handles never-seen-before queries — approximately 15% of Google searches are queries it has never encountered; RankBrain maps them to similar known queries
- Learns from user behaviour — if users consistently skip one result and click another, RankBrain adjusts rankings accordingly
How RankBrain Affects SEO
RankBrain reinforces the importance of search intent match. Stuffing keywords into content doesn't fool RankBrain — it looks at whether users engage with your result. Pages with high CTR and low pogo-sticking signal quality to RankBrain.
Optimising for RankBrain
- Match search intent precisely
- Write compelling title tags to maximise CTR
- Ensure content fully satisfies the query so users don't return to Google
- Improve dwell time with in-depth, engaging content