Subtitle Converter

Subtitles come in two everyday formats that refuse to meet: SRT, the classic numbered format used by desktop players and editing suites, and WebVTT, the only format HTML5 video and most web platforms accept. The difference looks tiny — a WEBVTT header and a dot instead of a comma in timestamps — yet a file in the wrong format is silently ignored by the player, and editing timestamps by hand is hopeless on anything longer than a trailer.

This tool fixes the three most common subtitle problems in one place, entirely in your browser: convert between SRT and VTT, shift every timestamp by a chosen number of milliseconds or seconds, and renumber cues after manual editing. Load a .srt or .vtt file or simply paste the subtitle text; nothing is uploaded, so unreleased videos and private transcripts stay on your device.

The parser is deliberately forgiving: byte-order marks, Windows CRLF line endings, extra blank lines between cues and missing sequence numbers are all handled without complaint. Conversion to WebVTT adds the required header and rewrites 00:01:02,500-style timestamps to the dot notation; conversion back to SRT renumbers cues from 1 and strips WebVTT-only markup — and because SRT simply cannot express VTT positioning or styling, the tool tells you how many cues lost that data rather than failing or faking it.

Timing shift accepts positive and negative offsets: delay subtitles that show up before the speech, or pull forward subtitles that lag behind it. Cues that would end up before the start of the video are clamped at 00:00 and reported. When the result looks right, download it with the correct extension or copy it straight to your clipboard.