YouTube has no built-in way to watch multiple videos simultaneously. Comparing two tutorials or checking two cuts of the same video leaves you switching between tabs.
A free browser-based player solves it, with nothing to install.
Method: Use Multi Video Player (Free, No Extension Needed)
Multi Video Player is a free browser-based multi-video player that works with YouTube, Twitch, Vimeo, Kick, and 30+ other platforms. You can start watching multiple YouTube videos side by side in under a minute.
Step-by-Step Instructions
Step 1. Open multivideo.io in your browser. The free tier needs no account and no download.
Step 2. Go to YouTube and open the first video you want to watch. Copy the URL from your browser address bar.
Step 3. Paste the YouTube URL into Multi Video Player's input field and click Add.
Step 4. Return to YouTube, open your second video, and copy its URL. Paste it into Multi Video Player and click Add again.
Step 5. Both videos now appear in the player. Use the column selector to set them side by side (2 columns). Each video keeps its own controls, so you pause, seek, and set the audio on one without touching the other.
Getting the Best Side-by-Side Layout
For two videos side by side, select 2 columns. Each video then fills half the available width.
For three videos in a row, select 3 columns. For four videos, select 2 for a 2x2 grid or 4 for a single row.
Use the merge feature for a tighter split-screen: click the merge button on one video, then click another to combine them in a single container. Merged containers suit frame-by-frame comparison.
Practical Uses for Side-by-Side YouTube Viewing
Tutorial comparison: watch two instructors teach the same programming concept or cooking technique side by side, and keep the explanation that lands.
Video editing review: run two versions of an edit at the same time and compare pacing, color, and structure.
Language learning: play a video in your target language next to the same content in your native language.
Research: put news segments from two outlets on the same story next to each other and compare the framing.
Content creation: study how other creators handle hooks, pacing, and presentation, then apply what works to your own videos.
Browser Extensions
Browser extensions for YouTube side-by-side viewing exist. Most of them cover YouTube alone, and you install and update them per browser. Multi Video Player covers 30+ platforms, installs nothing, and runs in any browser, phones included.
A YouTube tutorial next to a live Twitch demonstration is the case extensions cannot cover, and the one Multi Video Player was built for.