1
Paste a YouTube URL
Copy any YouTube video link and paste it into the Video URL field on the right panel, then click Load Video.
2
Check the subtitle library
After loading, SubSync automatically searches the library for subtitles matching that video. If found, they appear under Subtitles in Library — just click + Add to load them instantly.
3
Or upload your own .srt file
Have your own subtitle file? Use Upload Your Own in the right panel. Each of the 3 tracks accepts its own .srt file — you can mix library and uploaded tracks freely.
4
Label your tracks
Click the label field on any track card and rename it — English, Thai, Notes, etc. The label shows in the subtitle row below the video.
5
Press play and watch
All active subtitle tracks sync in real time. The row glows when a cue is active. Use ✕ to clear any track.
💡 Up to 3 subtitle tracks simultaneously
Why does the video say "Watch on YouTube" or show an error?
Some videos disable embedding — a restriction set by the video owner, not SubSync. Try a different video; most public music videos and tutorials work fine.
Where do I find .srt subtitle files?
The subtitles are out of sync — what do I do?
The SRT timestamps need to match the specific video version. Different uploads of the same video (official vs remaster) may have different timings.
Can I use this on my phone?
SubSync is currently optimised for desktop browsers. Mobile support is planned in a future update.
Is my data saved anywhere?
Uploaded files are only in your browser's memory for the current session. Library subtitles are stored on our server tied to video ID only — no personal data is collected.
SubSync is a free tool for watching YouTube videos with multiple subtitle tracks simultaneously — perfect for language learners, translators, and anyone following along in more than one language.
Built as a side project. If it's useful to you, consider supporting on Patreon — it helps keep the server running and motivates new features.
Current features
• Up to 3 simultaneous subtitle tracks
• Community subtitle library (by video ID)
• Upload your own .srt files
• Real-time sync at 80ms intervals
• Rename tracks with custom labels
Planned features
• User accounts to save subtitle sets
• Submit subtitles to the community library
• Subtitle offset adjustment slider
• Mobile layout