Subconverter
Subconverter converts subtitle formats, synchronizes SRT and SUB/IDX files, and helps fix subtitle timing issues.
About Subconverter
Subconverter is a free web tool for converting between subtitle formats and adjusting timing. It handles text-based formats such as SRT, VTT, SSA/ASS, TTML and iTT, and converts image-based SUB/IDX and SUP files to SRT using Tesseract OCR.
It also offers timestamp shifting, partial shifting, FPS and drift correction, conversion to UTF-8, cleaning, validation, merging, and extraction of embedded tracks from MKV and MP4 files. Files are uploaded for processing with no signup required and are removed after each tool's temporary retention window; OCR results vary with image quality and language complexity.
Key features
- Convert SUB/IDX image subtitles to SRT using OCR
- Convert SUP Blu-ray subtitles to SRT
- Shift all timestamps or fix specific sections
- Correct gradual desync with FPS and drift fixer
- Convert to VTT, SBV, LRC, TTML, and iTT
- Extract embedded subtitle tracks from MKV and MP4
- No signup required to use the tools
- Supports text-based and image-based subtitle formats
- Covers conversion, sync adjustment, cleaning, and encoding fixes in one site
- OCR results depend on image quality and language complexity
Subconverter at a glance
- Website
- subconverter.com
- Category
- Online Tools › Everyday Web Utilities
- Type
- Website
- Pricing
- Free
- Platforms
- Web
- Open source
- Not stated
- Language
- English
- Last checked
- Oct 5, 2026 · Online when checked
- Listed
- Oct 5, 2026
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Subconverter FAQ
Which subtitle formats are supported?
How accurate is SUB/IDX to SRT conversion?
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