Subtitle Format Converter
Convert subtitles between SRT, VTT, ASS/SSA and plain text — free, instant, nothing uploaded
The input format is detected automatically from the file's content, not just its extension.
100% private — Files are converted right in your browser and never uploaded to any server.
How it works
- 1
Drop in a subtitle file — SRT, VTT, ASS or SSA.
- 2
Pick the output format you need.
- 3
Click convert and download the result.
Subtitle formats differ mostly in time syntax
Format detected from content
The input format is sniffed from actual file markers — a WEBVTT header, an ASS [Script Info] block — not from the file extension, which some video platforms serve incorrectly.
SRT, VTT and ASS/SSA round-trip
SubRip, WebVTT and SubStation Alpha files convert into any of the four output choices, including a plain-text TXT transcript — useful when a translation workflow only needs the spoken lines.
Cue timings stay intact
Start and end timestamps carry across every conversion, so subtitles stay in sync with the video after switching formats. Files are read and written as UTF-8, preserving accented subtitles.
Frequently asked questions
How is the input format detected?⌄
By reading the file's actual content — a WEBVTT header, ASS/SSA's [Script Info] section, or plain SubRip numbering and timestamps — not just the file extension, so a mislabeled file still converts correctly.
Will I lose any timing precision converting to ASS/SSA?⌄
ASS timestamps use centiseconds (hundredths of a second) instead of SRT/VTT's milliseconds, so times are rounded to the nearest 10ms. This is invisible in playback.
Is anything uploaded to your servers?⌄
No — parsing and conversion both happen entirely in your browser. The file never leaves your device.
Related tools
What Is a Subtitle Format Converter?
A subtitle format converter rewrites caption files between the formats that players and platforms actually accept: SubRip SRT, WebVTT, SubStation Alpha ASS and SSA, plus plain TXT for reading without timings. This tool sniffs the real format from file content rather than trusting the extension, parses cues with the production-proven routines shared with the AI subtitle pipeline, and writes the format you select, accepting subtitle files up to 10 MB.
How cue timestamps survive the trip
Every cue keeps its start and end times through detection, parsing, and rendering, so dialogue stays in sync after conversion. A WEBVTT header or Script Info and Dialogue markers identify VTT and ASS inputs, anything else is treated as SRT, and a file that yields zero cues is rejected as an invalid subtitle file instead of producing an empty download.
Which output format each player expects
- VTT for HTML5 video and web players, preselected because browsers ask for it natively.
- SRT for desktop players, editors, and upload flows that still treat SubRip as the common denominator.
- ASS or SSA when styled dialogue, karaoke timing, or positioned lines must be preserved for a compatible player.
- TXT when you only need the spoken lines as a transcript for notes, quotes, or search.
Styling that cannot cross formats
Not everything travels: ASS colors, fonts, and screen positions collapse when flattened into SRT or VTT, and TXT drops all timing on purpose. Overlapping or malformed cues may also need a cleanup pass in an editor, since the converter preserves content faithfully rather than re-timing it.
Why caption files never leave this browser tab
Detection, parsing, and rendering all execute on your device with no upload calls, no server routes, and no registration API in the tool code, so caption bytes are never posted anywhere. The converted file is assembled locally and offered as an immediate download.
Match the output to the player first and the captions simply play where you drop them.
Last updated · 2026-09-01