Subtitle Converter Online
Convert between SRT, WebVTT, and ASS/SSA formats instantly in your browser. Check line length and line count to meet Netflix, YouTube, and broadcast standards. 100% private – your files never leave your device.
Input (Drag & Drop or Paste)
Line Check & Wrap
Output
Line Check Issues (Top 30)
No issues detected.
Subtitle Format Comparison
| Feature | SRT | WebVTT | ASS / SSA |
|---|---|---|---|
| File Extension | .srt | .vtt | .ass / .ssa |
| Time Format | 00:00:00,000 | 00:00:00.000 | 0:00:00.00 |
| Styling Support | Basic (HTML tags) | CSS + cue settings | Full (fonts, colors, positions) |
| Best For | Most video players | Web / HTML5 video | Anime, karaoke, styled subs |
| Netflix Compatible | ✓ (Preferred) | ✓ | ✗ (convert to SRT) |
| YouTube Compatible | ✓ | ✓ | ✗ (convert needed) |
Frequently Asked Questions
Netflix prefers SRT format with specific guidelines: max 42 characters per line, max 2 lines per subtitle, minimum 1 second duration, and no more than 17 characters per second reading speed. Use the "Line Check" feature on this page to validate your subtitles against these requirements.
YouTube doesn't support ASS format natively. Use this converter to convert ASS to SRT or VTT. Note that advanced ASS styling (custom fonts, colors, positions) will be lost during conversion – only the plain text and timing will be preserved.
When enabled, the converter automatically breaks long lines at word boundaries to fit within your specified maximum line length. This helps create cleaner subtitles that are easier to read and meet platform requirements. The default is 42 characters, which is the Netflix standard.
100% private. All processing happens entirely in your browser using JavaScript. Your subtitle files are never uploaded to any server. We don't store, log, or have any access to your content. You can even use this tool offline once the page loads.
This tool converts between formats but doesn't change timing or extract subtitles from video. For timing adjustments, use Subtitle Sync . To extract embedded subtitles from videos, use Subtitle Extractor . If you need video compression or format conversion, check out ShrinkFile.
Need to generate subtitles from scratch?
VoiceWeaver for macOS uses hardware-accelerated Whisper AI to transcribe audio and video files directly on your Mac. Easily export highly accurate, perfectly synced SRT or VTT subtitles without uploading your media to the cloud.
Learn More about VoiceWeaverWorking with large video files?
ShrinkFile brings professional-grade video compression to your browser. Compress 4K videos, convert between formats, and extract audio effortlessly without uploading anything to the cloud.
Learn More about ShrinkFile