Convert a WebVTT subtitle file to the style-capable ASS/SSA format locally - with a valid default style as a starting point. No upload.
Running locally on your device ...
Running locally on your device ...
0%
Your files never left your device
No. Everything runs in your browser - your file never leaves your device. How this is verifiable
Anyone who has exported a web subtitle file (.vtt) from a browser editor, a video platform or their own captioning tool, and now wants to shape it further in Aegisub - say for a fan release with a custom karaoke effect or special typography - needs ASS as the starting format. This tool handles exactly that step.
From every WebVTT cue, the tool takes the start and end time plus the plain text and enters both into a complete ASS structure: a [Script Info] header, a single base style in the [V4+ Styles] block, and one Dialogue line per cue in the [Events] section. WebVTT's millisecond time base is converted along the way to the hundredths-of-a-second ASS expects.
No server is involved: the script that reads your file and writes the new .ass runs entirely in your own browser tab. If your .vtt carries no recognisable timeline, the process stops with an understandable message instead of producing an empty file.
| Input formats | VTT |
|---|---|
| Output format | ASS |
| Batch processing | No |
| Processing | Locally in your browser (JavaScript) |
| File upload | None |
Limitations: Produces an ASS file with a single default style (Arial, white) - it is the basis for further editing, not already styled. WebVTT positioning hints are not translated into ASS positioning. The tool converts, it does not translate into another language.
No. The conversion runs entirely locally in your browser; the file never leaves your device.
No. It contains a plain default style as a starting point; you add font, colour and position in an ASS editor such as Aegisub.
Yes. The start and end time of each cue is carried over (rounded to hundredths of a second), and multi-line subtitles stay multi-line.
Yes, there is the sibling tool "Convert ASS to VTT" for that.