Subtitle Timing Shifter
The ViralMint Subtitle Timing Shifter is a free tool that fixes out-of-sync SRT subtitles by shifting every cue's timestamps by a fixed offset — instantly, in your browser, with nothing uploaded. If your subtitles consistently appear a second or two too early or too late, paste or upload the .srt file, set how many seconds to shift them (later or earlier), and download the corrected file. It runs entirely on your own device using plain text parsing — no sign-up, no server, no privacy risk. The tool moves all subtitles by the same amount, which fixes the most common sync problem: a constant delay between the audio and the captions. Every timestamp is recalculated and clamped so it never drops below zero. Use it to repair a downloaded subtitle file that's off by a fixed amount, or to nudge your own captions back into sync after an edit.
All 3 subtitles will appear 2s later. First cue: 00:00:01,000 --> 00:00:04,000 → 00:00:03,000 --> 00:00:06,000
How to fix out-of-sync subtitles
- Load your file — paste the SRT text, or click “Upload .srt”.
- Set the offset — type how many seconds off it is, and pick Later (captions show too soon) or Earlier (captions show too late).
- Check the preview — the tool shows how many cues will shift and the new time of the first one.
- Download the corrected .srt and load it back into your player or editor.
Not sure how far off it is? Note the timecode where a line is spoken in the video, compare it to that line's subtitle time, and the difference is your offset.
How subtitle timing shifting works
Each SRT cue has a start and end time like 00:00:04,500 --> 00:00:08,200. The
tool converts every timestamp to milliseconds, adds your offset (positive for later,
negative for earlier), clamps the result at zero, and reformats it back to
HH:MM:SS,mmm. Only the timing lines change — your indices and subtitle text are
left exactly as they were.
When a shift won't fix it (subtitle drift)
A constant shift only works when the subtitles are off by the same amount the whole way through. If your captions start in sync but drift further out as the video plays, that's almost always a frame-rate mismatch (for example a 23.976 fps file paired with 25 fps subtitles). Fixing drift means stretching the timing proportionally, not shifting it by a fixed offset — a different operation this tool doesn't do yet. For the far more common constant-delay case, a shift is the fix.
Frequently asked questions
How do I fix subtitles that are out of sync?
If your subtitles are consistently early or late by the same amount, paste or upload the .srt file, set how many seconds to shift them (later if they appear too soon, earlier if too late), and download the corrected file. The tool recalculates every timestamp by your offset. This fixes the most common problem — a constant delay between the audio and the captions.
What does shifting subtitle timing do?
It adds (or subtracts) a fixed number of seconds to every subtitle's start and end time. A 2-second 'later' shift moves a cue at 00:00:04 to 00:00:06, and so on for the whole file. The text and order stay identical — only the timing moves. Times are clamped at zero so they never go negative.
Is my subtitle file uploaded anywhere?
No. The entire tool runs in your browser using plain text parsing — your file never leaves your device, there's no server, and there's no sign-up. You can use it offline once the page has loaded.
It fixes a constant delay — what about subtitles that drift?
A fixed shift only fixes subtitles that are off by the same amount the whole way through. If captions start in sync but drift further out as the video plays, that's usually a frame-rate mismatch (e.g. 23.976 vs 25 fps) and needs the timing stretched, not shifted — a constant offset won't fix it. This tool handles the constant-offset case, which covers the large majority of sync problems.
Does it work with .srt and .vtt files?
It's built for SubRip (.srt) files and outputs .srt. The parser is lenient — it also reads timestamps written with a dot (VTT-style 00:00:04.500) — but the download is always SRT format. A dedicated SRT↔VTT converter is a natural companion tool.
Stop resyncing subtitles by hand
ViralMint transcribes locally with Whisper and burns in perfectly-timed, word-by-word captions automatically — no offset math, no drift.