SRT Subtitle Shifter
Resync subtitles that run early or late: shift every timestamp in a .srt file forward or backward by a fixed offset. Runs entirely in your browser — nothing is uploaded.
What this tool does
Subtitles out of sync with the video? This tool shifts every timestamp in a
SubRip (.srt) subtitle file forward or backward by the same fixed offset, so
the whole track lines up again. Paste your subtitles, type how far to move them,
and copy the corrected file back out. Nothing is uploaded — it runs entirely in
your browser, works offline, and needs no sign-up.
How to use it
- Paste the full contents of your
.srtfile into the box. - Enter the Offset:
- a positive number to delay the subtitles (they appear later), or
- a negative number to advance them (they appear earlier).
- Pick the Unit — seconds (fractions like
2.5are fine) or milliseconds. - Copy the shifted subtitles from the output.
What gets changed
Only the timing lines are rewritten — for example
00:00:01,000 --> 00:00:04,000. The cue numbers and the dialogue text are kept
exactly as they were, and the file's line endings (Windows \r\n or Unix \n)
are preserved.
Any timestamp that would land before the start of the video is clamped to
00:00:00,000, so a large negative shift never produces a negative time.
Examples
| Offset | Unit | Effect on 00:00:01,000 --> 00:00:04,000 |
|---|---|---|
2.5 | seconds | 00:00:03,500 --> 00:00:06,500 (subtitles delayed) |
-0.5 | seconds | 00:00:00,500 --> 00:00:03,500 (subtitles advanced) |
750 | milliseconds | 00:00:01,750 --> 00:00:04,750 |
FAQ
Which way should I shift?
If the subtitles appear too early (before the words are spoken), use a positive offset to delay them. If they appear too late, use a negative offset to advance them.
Does it handle fractional seconds?
Yes — enter values like 1.25 seconds,
or switch to milliseconds for exact frame-level nudges.
Is my file uploaded anywhere?
No. The shift happens locally in your browser, so your subtitles never leave your device, and it keeps working offline once the page has loaded.
My subtitles drift — they're fine at the start but off by the end.
This tool applies one constant offset to the whole file, which fixes a uniform lead/lag. A growing drift means a frame-rate mismatch (e.g. 23.976 vs 25 fps), which needs a linear time-stretch rather than a flat shift.
What format does it expect?
Standard SubRip (.srt): a cue number, a
HH:MM:SS,mmm --> HH:MM:SS,mmm timing line, then one or more lines of text,
with a blank line between cues.
Developer & Automation Access
Run it from the terminal
Same engine as this page, headless — via the gizza CLI:
gizza tool srt-shift "1
00:00:01,000 --> 00:00:04,000
First line of dialogue." 'offset=2.5'New to the CLI? Get gizza →
Open it by URL
Pre-fill and auto-run this tool with query parameters — the names match the API/CLI:
https://gizza.ai/tools/srt-shift/?srt=1%0A00%3A00%3A01%2C000%20--%3E%2000%3A00%3A04%2C000%0AFirst%20line%20of%20dialogue.&offset=2.5&unit=secondsMachine-readable descriptor: tool.json — title + parameters JSON Schema for agents.