Auto Resizer for YouTube™

Auto-fits the YouTube player to your window, screen and playback quality. 4K and multi-monitor aware, with a pop-out player.

YouTube only ever grows its player to the size it wants. On a 1600px window a 4K video still sits in a 1112px box, with a recommendations rail permanently occupying 400px to its right and a large empty gap underneath. This extension flips the order: the player claims space first, the recommendations rail takes what is left, and it wraps below when it no longer fits. WHAT IT DOES • Match the quality — caps at the video's native resolution, then shrinks to the largest 16:9 size the window can hold. A 4K video on a 1600x863 window goes from 1112px to 1392px wide. • Display adaptation — works out the quality you actually need from player width multiplied by your screen's pixel density, then asks YouTube for it. Drag the window from a Retina laptop to a 4K monitor and the quality is recalculated. You can set a ceiling (default 4K). • Pop-out player — a button in the player controls opens the current video in its own window and resumes from the same second. Only the player is kept; the masthead, recommendations, video info and comments are all collapsed. The window size is corrected in a closed loop until the content area matches the video's aspect ratio, and you can choose which display it opens on. • Quality lock — pin every new video to a quality you choose (2160p down to 480p). If a video does not offer it, the highest available is used instead. • Zero-gap layout — removes the padding beside and above the player. PRIVACY No data collection. No server, no analytics, no remote code, no outbound connections of any kind — the source contains no fetch or XMLHttpRequest calls at all. Your settings live in the browser's own storage and sync through your Google account; the developer cannot see them. Full policy: https://labs.moneyai168.com/projects/auto-resizer-for-youtube/privacy.html OPEN SOURCE MIT licensed. Source, tests and issue tracker: https://github.com/boboidvtw/auto-resizer-for-youtube --- YouTube™ is a trademark of Google LLC. This extension is an independent project and is not affiliated with, sponsored by, or endorsed by Google LLC or YouTube.