Convert MP4 to SRT Online Free
Extract subtitle tracks from MP4 videos into standalone SRT files. Perfect for accessibility compliance, translation workflows, and subtitle editing.
By ChangeThisFile Team · Last updated: March 2026
ChangeThisFile extracts SRT subtitle files from MP4 videos using FFmpeg on a secure server. Upload your video and get subtitle tracks as downloadable SRT files. Free with automatic file deletion after processing.
Convert MP4 to SRT
Drop your MP4 file here to convert it instantly
Drag & drop your .mp4 file here, or click to browse
Convert to SRT instantly
MP4 vs SRT: Format Comparison
Key differences between the two formats
| Feature | MP4 | SRT |
|---|---|---|
| Content type | Video container with multiple streams | Plain text subtitle file |
| File size | Large (MB to GB) | Tiny (usually under 100KB) |
| Subtitle support | Can embed multiple subtitle tracks | Single subtitle track with timing |
| Compatibility | Video players and editing software | Universal subtitle format |
| Editing | Requires video editing software | Edit with any text editor |
| Purpose | Video playback with embedded subtitles | Standalone subtitle file for any player |
| Timing format | Various subtitle formats embedded | Standard SRT timing (HH:MM:SS,mmm) |
When to Convert
Common scenarios where this conversion is useful
Accessibility compliance
Extract captions from promotional videos to provide downloadable subtitle files for hearing-impaired viewers and meet WCAG guidelines.
Translation workflows
Get subtitle text from training videos to send to translators, creating multilingual subtitle files without re-transcribing content.
Subtitle editing
Extract existing subtitles from MP4 files to edit timing, fix typos, or reformat text using specialized subtitle editing software.
Content analysis
Extract spoken content from recorded meetings, webinars, or interviews to create searchable transcripts and documentation.
How to Convert MP4 to SRT
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1
Upload your MP4 video
Drag and drop your MP4 file onto the converter, or click browse. The file is uploaded over an encrypted connection.
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2
FFmpeg extracts subtitles
The server uses FFmpeg to extract subtitle tracks from your MP4 video. This typically takes a few seconds.
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3
Download the SRT file
Save your extracted subtitle file. The server copy is automatically deleted after processing.
Frequently Asked Questions
Yes, completely free with no limits. ChangeThisFile uses FFmpeg to extract subtitles on secure servers with automatic file deletion.
The converter will return an error if your MP4 contains no subtitle tracks. Only videos with embedded captions or subtitle streams can be processed.
The converter extracts the first available subtitle track by default. If your MP4 has multiple language tracks, it will extract the primary one.
Up to 50MB per MP4 file. Since only subtitle data is extracted (not video), even large files process quickly - usually within 5-10 seconds.
Yes, all original timing is maintained including start times, end times, and duration. The output follows standard SRT format (HH:MM:SS,mmm).
Videos are uploaded over encrypted HTTPS, processed on secure servers, and automatically deleted immediately after subtitle extraction. We never store content.
All embedded subtitle formats (VTT, ASS, etc.) are converted to standard SRT format, which works with virtually any video player or editing software.
This usually means your MP4 has very few subtitles or short duration captions. Verify your original video displays subtitles when played.
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