Convert SUB to SRT
Free online SUB to SRT converter. No signup required.
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Max file size: 100 MB
When to convert SUB to SRT
Use this conversion when your destination needs SRT and you have a SUB source. Keep the original so you can compare the result or try another supported format.
Check the output in your target application. Format conversion may change unsupported features, metadata or precision; retain the original file as your reference.
SUB vs SRT: Format Comparison
Side-by-side comparison of the source and target formats.
| Property | SUB (Source) | SRT (Target) |
|---|---|---|
| Extension | .sub | .srt |
| Full Name | MicroDVD Subtitle | SubRip Subtitle |
| Compression | Varies | Varies |
| File Size | Varies | Medium |
| Best For | Legacy subtitle files for video content | Movie and TV show subtitle files for media pl… |
| Browser Support | Varies | Wide |
How to Convert SUB to SRT
Follow these simple steps to convert your file in seconds.
Choose a SUB file
Select or drop one file up to 100 MB. Its extension must match this converter. Availability is checked before transfer.
Convert to SRT
Check the output in your target application. Format conversion may change unsupported features, metadata or precision; retain the original file as your reference.
Download and check the result
Use Download after conversion completes. Open the result and check its content, quality and formatting before sharing it. Download links expire one hour after upload finishes. Uploaded and converted files are removed automatically by regular cleanup. Files may become unavailable sooner when the service restarts.
Tips for Converting SUB to SRT
Practical advice to get the best results from this conversion.
Why this conversion is worth doing
MicroDVD Subtitle has a known limitation: frame-based timing requires knowledge of video frame rate for correct display. SubRip Subtitle addresses this with a key advantage: universally supported by virtually all media players and video platforms. Converting from SUB to SRT is most worthwhile when this specific trade-off matters for the way you intend to use the file.
Match the format to the actual workflow
MicroDVD Subtitle is most commonly used for legacy subtitle files for video content, while SubRip Subtitle is the standard for movie and tv show subtitle files for media players. If your workflow is closer to the second pattern, converting makes sense. If you are still working in a context where SUB is the norm, converting may create unnecessary compatibility friction with collaborators or tools that expect the source format.
Watch for this limitation in the SRT output
SubRip Subtitle has its own limitation worth understanding before you commit: no support for text styling, positioning, or color formatting. After the conversion completes, open the SRT file and verify that this limitation does not affect your specific use case — for some workflows it is irrelevant; for others it can be a deal-breaker.
Match the subtitle format to your player or platform
Different players and platforms require specific subtitle formats. SRT is the most universally supported format for offline players. VTT (WebVTT) is the standard for HTML5 video on the web. ASS/SSA supports advanced styling but has limited player compatibility. Choose the format your target platform natively supports to avoid display issues.
Understanding SUB and SRT Formats
Learn about the source and target file formats to understand what happens during conversion.
Source Format
MicroDVD Subtitle
text/x-subSUB (MicroDVD Subtitle) is a frame-based subtitle format that uses frame numbers rather than timestamps for timing synchronization. Each line contains start and end frame numbers enclosed in curly braces followed by the subtitle text, with pipe characters separating multiple display lines. SUB requires knowing the video frame rate to correctly synchronize subtitle display timing.
Advantages
- Frame-accurate timing that precisely matches video frame boundaries
- Simple format that is easy to parse and generate programmatically
- Supported by many popular media players including VLC
Limitations
- Frame-based timing requires knowledge of video frame rate for correct display
- Changing the video frame rate misaligns all subtitle timing
- Less intuitive than timestamp-based formats for manual editing
Common Uses
- Legacy subtitle files for video content
- Frame-accurate subtitle synchronization for specific video encodes
- Subtitle conversion source for timestamp-based format output
Target Format
SubRip Subtitle
application/x-subripSRT (SubRip Subtitle) is the most widely used text-based subtitle format, storing numbered subtitle entries with timestamps and plain text content. Each entry contains a sequence number, start and end timestamps in HH:MM:SS,mmm format, and one or more lines of text. SRT is supported by virtually every media player and video platform due to its simplicity and ubiquity.
Advantages
- Universally supported by virtually all media players and video platforms
- Extremely simple plain-text format that is easy to create and edit manually
- Supported for upload on YouTube, Vimeo, and most streaming platforms
Limitations
- No support for text styling, positioning, or color formatting
- No support for karaoke-style word-by-word timing
- Cannot specify screen position or region for subtitle display
Common Uses
- Movie and TV show subtitle files for media players
- YouTube and streaming platform subtitle uploads
- Fan-created subtitles and translation projects
Frequently Asked Questions
Common questions about converting SUB to SRT.
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