YouTube's recommendation system learns every day from over 80 billion pieces of information it calls signals.
Source: YouTube, On YouTube's recommendation system (2021)
YouTube's recommendation system learns from 80 billion signals daily. For the homepage, it primarily uses your watch history. For Up Next, it uses the video you are currently watching. Videos are ranked by viewer personalisation and content performance, not by subscriber count or publish time.
YouTube does not promote videos to audiences — it finds audiences for videos. The system ranks each video based on two categories: how well it is personalised to a specific viewer, and how well it performs when offered to viewers. Every claim on this page comes from official YouTube Help or the YouTube Creator Blog.
YouTube's recommendation system learns every day from over 80 billion pieces of information it calls signals.
YouTube, 2021For Home recommendations, YouTube's system primarily relies on your watch history to decide which videos to surface.
YouTube, 2024YouTube uses classifiers to identify borderline content and demotes it in recommendations rather than removing it entirely.
YouTube, 2021YouTube's recommendation system learns every day from over 80 billion pieces of information it calls signals.
Source: YouTube, On YouTube's recommendation system (2021)
For Home recommendations, YouTube's system primarily relies on your watch history to decide which videos to surface.
Source: YouTube, How YouTube recommendations work (2024)
For Up Next recommendations, YouTube uses the video you are currently watching as the main signal when suggesting the next video.
Source: YouTube, How YouTube recommendations work (2024)
YouTube uses satisfaction surveys — asking viewers to rate videos — to measure satisfaction beyond just watch time as an input to recommendations.
Source: YouTube, How YouTube recommendations work (2024)
YouTube informs recommendations from clicks, watch time, survey responses, sharing, likes, and dislikes.
Source: YouTube, On YouTube's recommendation system (2021)
In 2011 YouTube discovered that clicking on a video does not mean you actually watched it, and shifted to prioritising watch duration over click-through rate.
Source: YouTube, On YouTube's recommendation system (2011)
YouTube uses classifiers to identify borderline content and demotes it in recommendations rather than removing it entirely.
Source: YouTube, On YouTube's recommendation system (2021)
After YouTube began demoting borderline content in 2019, watchtime from non-subscribed recommended borderline content dropped 70% in the US.
Source: YouTube, On YouTube's recommendation system (2019)
Publish time is not known to impact a video's long-term performance in YouTube recommendations.
Source: YouTube, YouTube's Recommendation System (2024)
YouTube officially advises creators to prioritise consistent quality content over a high frequency of uploads.
Source: YouTube, YouTube's Recommendation System (2024)
No. YouTube's recommendation system does not use subscriber count as a direct ranking signal. Videos are ranked based on viewer personalisation and per-video performance data, not channel size.
Watch history combined with how well a video performs when offered to viewers. The YouTube blog confirms the system learns from over 80 billion signals daily, with watch history and satisfaction surveys being primary inputs.
No. YouTube's official guidance states that publish time is not known to impact a video's long-term performance in recommendations.
YouTube uses classifiers to identify borderline content and demotes it in recommendations rather than removing it entirely. This approach resulted in a 70% drop in watchtime on recommended borderline content in the US in 2019.
No. YouTube officially states that the algorithm does not penalise creators for taking time off, and that a sustained presence is advisable but a single break will not hinder a channel's potential.