Subtitle Format Converter

Subtitle files are format-fragile. SRT works in desktop video editors and most CMS platforms. WebVTT is what browsers require for the <track> element and what YouTube accepts on upload. ASS/SSA carries per-cue positioning, font, and color data that no other format supports. SBV is what YouTube Studio generates when you export captions. Plain TXT is what translators and transcription pipelines want. None of these formats read each other natively, which means every subtitle file you produce eventually needs to be in a different format for a different destination.

The AT USE Subtitle Format Converter handles conversion in every direction across this matrix: SRT, WebVTT, ASS/SSA, SBV, and plain TXT. Drop a file in, pick the output format, and download the result. Timing is preserved exactly in all directions. Styling — ASS's per-cue font, position, and color override codes — is preserved when the target format supports it and stripped cleanly when it does not (SRT has no styling support; it receives the plain text of each cue with no extra characters). The converter validates each cue against the target format's rules so you never download a broken track file.

Everything runs locally in your browser. Your subtitle file is never sent to any server. This matters for subtitle files containing confidential interview transcripts, pre-release episode scripts, or internal training content that should not leave your device.

Format reference

SRT — the widest-compatibility format. Sequential cue index, HH:MM:SS,mmm --> HH:MM:SS,mmm timestamps, plain text. Supported by every desktop video editor, most CMS platforms, and all broadcast delivery systems.

WebVTT (VTT) — required for HTML5 <video> tracks. Comma replaced by period in the timestamp (HH:MM:SS.mmm --> HH:MM:SS.mmm), with a mandatory WEBVTT header on the first line. YouTube accepts VTT for caption uploads.

ASS/SSA — the format for advanced styling. Stores per-cue positioning, custom fonts, karaoke timing, and color overrides in header blocks. Supported by VLC, Kodi, MPC-HC, and most media player software. Not supported by HTML5 or YouTube.

SBV — YouTube's proprietary caption export format. Timestamp format 0:00:00.000,0:00:00.000 without a cue index. Frequently encountered when downloading auto-generated captions from YouTube Studio.

Plain TXT — dialogue text only, one cue per line, all timestamps removed. Used for translation handoffs, transcript review, and LLM processing pipelines.

What survives conversion and what does not

Timing survives in all directions without rounding or drift. ASS styling data (font, color, position, rotation) survives ASS-to-ASS only; ASS-to-SRT and ASS-to-VTT strip styling and deliver clean text. VTT cue settings (position, alignment, line) survive VTT-to-ASS conversion and are dropped for VTT-to-SRT. SBV's cue structure converts cleanly to SRT with cue indices added. Encoding is normalised to UTF-8 on output regardless of whether the source file is Windows-1252, UTF-16, or ISO-8859-1.