Do I need to change anything in my HTML?

Point the element's src at the new .vtt file and set kind="subtitles" or "captions".

Does it change the timing?

No. Times are reformatted, not shifted.

Is the file uploaded?

No. Subtitles are converted in your browser.

Convert SRT subtitles to WebVTT

Turn a SubRip .srt file into a WebVTT .vtt for the web's <track> element. In your browser, nothing uploaded.

Browsers only load WebVTT for HTML5 video captions — point a <track> element at an .srt and nothing appears. Converting is mostly about details: WebVTT needs a WEBVTT header line, and its timestamps use a full stop where SRT uses a comma (00:01:02.500, not 00:01:02,500).

The converter rewrites the cue numbering and timestamps for the target format, so the file loads in a browser without hand-editing.

Which way to convert is detected from the file's contents rather than its name, so a VTT file someone saved with an .srt extension is still recognised as VTT.

Worth knowing. Character encoding matters with older subtitle files. If accented letters come out garbled, run the file through the text-encoding tool first to turn it into clean UTF-8.

Questions

Do I need to change anything in my HTML?: Point the <track> element's src at the new .vtt file and set kind="subtitles" or "captions".
Does it change the timing?: No. Times are reformatted, not shifted.
Is the file uploaded?: No. Subtitles are converted in your browser.

Everything the converter reads and writes →

Runs entirely in your browser. The file is never uploaded, so there is nothing for us to store, log or lose. No account, no watermark, no size paywall.