Add your SUB file
Drop one or more .sub files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
SUB to VTT
Converting a .sub file to .vtt extracts the document's content from its office package into a portable form. Free, private, and validated — the file never leaves your browser.
Private for supported formats — processed in your browser
Runs on your deviceConvert supported files
Drop SUB files here
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.About converting MicroDVD subtitles to WebVTT subtitles
Converting a .sub file to .vtt extracts the document's content from its office package into a portable form. A .sub file in the MicroDVD convention is a frame-based subtitle list: every line reads {startFrame}{endFrame}text, with a pipe character separating the lines inside one cue. Because the timing is expressed in frames rather than milliseconds, a MicroDVD file only means anything alongside the frame rate of the video it was timed to.
A .vtt file is a WebVTT caption document: a WEBVTT header followed by timed cues for HTML5 video and audio. It is the web-native caption format browsers expect for the track element. For this route the practical draw is first-class support in modern browsers and richer cue settings than SubRip — balanced against some legacy desktop players prefer .srt and mishandle WebVTT settings, which is worth knowing before you commit a large batch.
Why convert SUB to VTT?
The practical trigger for this conversion is usually a mismatch: with .sub, meaningless without the correct frame rate; the wrong value drifts the whole file. Switching to .vtt buys you first-class support in modern browsers, which is why it is the better fit for captioning HTML5 video with the track element. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
SUB vs VTT at a glance
| Aspect | MicroDVD subtitles (.sub) | WebVTT subtitles (.vtt) |
|---|---|---|
| Format type | Text-based — characters and structure, so there is no visual quality loss | Text-based — characters and structure, so there is no visual quality loss |
| How it stores data | each cue is one line: {startFrame}{endFrame} followed by the text, with | separating multiple display lines | files begin with WEBVTT and optional metadata headers before the first blank line |
| Strongest at | playing back subtitles that were timed against a specific video rip | captioning HTML5 video with the track element |
| Weak spot | meaningless without the correct frame rate; the wrong value drifts the whole file | some legacy desktop players prefer .srt and mishandle WebVTT settings |
Pick VTT as the output
Select .vtt in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if VTT is selectable, the route is real and validated.
Convert on your device
Press Convert. The package is unzipped in memory and its XML content parsed locally; nothing is uploaded.
Verify and download
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid VTT file. Outputs keep the original filename with the .vtt extension.
SUB to VTT questions, answered
Will converting SUB to VTT lose quality?
There is no visual quality to lose — sub is text-oriented and vtt is text-oriented, so the question is structural fidelity. Text, ordering, and basic structure are preserved; complex layout, embedded objects, and styling beyond the target's model are simplified.
Is it private to convert SUB files here?
Yes — the .sub file is processed inside your browser tab and never uploaded. The package is unzipped in memory and its XML content parsed locally; nothing is uploaded. Close the tab and the file is gone from memory.
Where will the VTT file work?
Chrome, Firefox, Safari, and Edge render .vtt through HTML track elements. Professional editors and many downloadable players also import it, though SubRip remains more common in older desktop workflows.
Will the VTT file be bigger or smaller than my SUB?
It depends on the content: files begin with WEBVTT and optional metadata headers before the first blank line. Convert one representative file first and compare before batch-processing a large set.
What happens to the metadata in my SUB file?
In .sub, there is no metadata section; the only header-like content is the frame-rate declaration, which is read on input and written on output. Re-encoding through the browser pipeline does not carry embedded metadata into the output, which doubles as a privacy scrub — check the exported file if you specifically need tags preserved.
Can I convert VTT back to SUB?
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .sub → .vtt → .sub is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.