Add your SRT file
Drop one or more .srt 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.
SRT to SUB
Converting a .srt file to .sub 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 SRT 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 SubRip subtitles to MicroDVD subtitles
Converting a .srt file to .sub extracts the document's content from its office package into a portable form. A .srt file is a SubRip subtitle document: numbered cues with start and end timestamps and plain caption text. It is the most common caption sidecar for video players, editors, and streaming toolchains that need a simple, widely understood text format.
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. For this route the practical draw is extremely compact — one line per cue and frame timing matches the source video exactly when the frame rate is known — balanced against meaningless without the correct frame rate; the wrong value drifts the whole file, which is worth knowing before you commit a large batch.
Why convert SRT to SUB?
The practical trigger for this conversion is usually a mismatch: with .srt, no standard support for advanced styling, voices, or regions. Switching to .sub buys you extremely compact — one line per cue, which is why it is the better fit for playing back subtitles that were timed against a specific video rip. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
SRT vs SUB at a glance
| Aspect | SubRip subtitles (.srt) | MicroDVD subtitles (.sub) |
|---|---|---|
| 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 | cues are blocks of an index, a timecode arrow line (HH:MM:SS,mmm --> HH:MM:SS,mmm), one or more text lines, and a blank separator | each cue is one line: {startFrame}{endFrame} followed by the text, with | separating multiple display lines |
| Strongest at | delivering captions alongside MP4 or MKV downloads | playing back subtitles that were timed against a specific video rip |
| Weak spot | no standard support for advanced styling, voices, or regions | meaningless without the correct frame rate; the wrong value drifts the whole file |
Pick SUB as the output
Select .sub in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if SUB 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 SUB file. Outputs keep the original filename with the .sub extension.
SRT to SUB questions, answered
Will converting SRT to SUB lose quality?
There is no visual quality to lose — srt is text-oriented and sub 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 SRT files here?
Yes — the .srt 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 SUB file work?
VLC, MPC-HC, and most desktop players read MicroDVD .sub, and Subtitle Edit converts it. Browsers do not. Novus Convert reads the frame rate from the file's own {1}{1} declaration and falls back to 23.976 when none is present; a binary VobSub .sub is rejected with an explanation rather than being parsed as text. MicroDVD output is written at 25 fps with that rate declared in the first line, so a converted file round-trips to the frame.
Will the SUB file be bigger or smaller than my SRT?
It depends on the content: each cue is one line: {startFrame}{endFrame} followed by the text, with | separating multiple display lines. Convert one representative file first and compare before batch-processing a large set.
Can I convert SUB back to SRT?
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .srt → .sub → .srt is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.