Adjust subtitle timing and sync with video. Fix delayed or early subtitles easily.
Format detected automatically.
Positive = delay, Negative = advance
1 = off. Fixes fps drift: 25/23.976 = 1.0427 (PAL speedup), 23.976/25 = 0.9590.
An SRT subtitle file is a sequence of cues: a numbered index, a timestamp line, the caption text, and a blank
separator line. Timestamps follow the pattern
HH:MM:SS,mmm, with a comma
before the milliseconds, as in
00:00:01,000 --> 00:00:05,000.
Players depend on that exact structure, so one mistimed cue can throw off every caption that follows it.
This adjuster applies one uniform shift: every timestamp line is converted to milliseconds, your offset is added to both the start and the end of each cue, and indexes and text pass through untouched. Positive values delay the subtitles, negative values advance them, and decimals are supported for fine, frame-boundary nudges. Any cue pushed before zero is clamped to 00:00:00,000 rather than breaking the file.
Whole-file offsets usually come from version mismatches: a broadcast edit with a scene removed, a skipped intro, or a re-export with a different lead-in. When subtitles drift progressively, in sync at the start and seconds off by the end, the real cause is typically a frame rate mismatch such as 23.976 fps film against 25 fps PAL speedup, and no constant offset can repair that. For neighboring text chores, compare revisions in the Text Diff Checker, clean up copy in the Text Editor, or reflow paragraphs with the Line Break Remover.
Both standard SRT (comma milliseconds, 00:00:01,000) and WebVTT (period milliseconds, 00:00:01.000). The format is detected automatically from the pasted content or uploaded file, and you can convert between the two with the output format selector.
Progressive drift almost always means a frame rate mismatch between the video and the subtitle track, for example 23.976 fps film sped up to 25 fps PAL. Set the speed scale factor to 25/23.976 (about 1.0427) or 23.976/25 (about 0.9590) to re-time the whole track proportionally, then apply any remaining constant offset.
Start and end times are clamped at 00:00:00,000 so the file stays valid. The cue effectively begins with the video instead of carrying a negative timestamp that players would reject.
Yes. Cues are renumbered sequentially in the output, which repairs files with duplicate or missing indexes. Caption text is preserved exactly as written; only indexes and timestamps are rewritten.
No. Parsing, adjustment, and the downloadable file are all generated locally in your browser. Nothing you paste is transmitted to a server.