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: a maximum of 42 characters per line, a maximum of 2 lines per subtitle, a minimum duration of 1 second, and no more than 17 characters per second. Use the Line Check feature on this page to validate your subtitles.
YouTube does not support ASS format natively. Use this converter to convert ASS to SRT or VTT. Advanced ASS styling such as custom fonts, colors, and positions will be lost during conversion; only plain text and timing are preserved.
When enabled, the converter automatically breaks long lines at word boundaries to fit within your maximum line length. This creates cleaner, easier-to-read subtitles and helps 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 a server. We do not store, log, or access your content. You can even use this tool offline once the page loads.
This tool converts between formats but does not 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.