Free tool
Subtitle shifter
Subtitles running early or late? This subtitle shifter moves every caption in an SRT, VTT, SBV, ASS or SSA file by the amount you type, or re-syncs the whole file from two lines you know the right times for.
- Free
- No sign-up
- Nothing is uploaded
Nothing is uploaded: your browser reads the file.
Subtitling your own recordings? NoteOwl transcribes them on your Mac, unlimited, and times every caption from the speech, so there is nothing to shift.
How it works
How do you shift subtitles?
Add the subtitle file, type how far to move it, in seconds or as minutes and seconds, and choose Later or Earlier. Every start and end time moves by that amount and nothing else changes. Download the file with its original name and ending.
- 1
Add the subtitle file
Drop an .srt, .vtt, .sbv, .ass or .ssa file, or paste its text.
- 2
Say how far
Type 2.5 for two and a half seconds, or 1:30, then pick Later or Earlier. Or sync from two points.
- 3
Download it
The shifted file keeps its format, its name and everything in it apart from the times.
How do you know how far to shift subtitles?
Compare one line. Note when it is spoken in the video and when its caption starts in the file; the difference is the shift. If the caption comes first, the subtitles are early, so move them later.
- 1
Find a clear line
Play the video and stop at a line of dialogue that starts cleanly, ideally early on.
- 2
Note two times
When the line is spoken in the video, and when its caption starts in the file.
- 3
Subtract
Spoken at 0:14.0 but captioned at 0:11.5? The captions are 2.5 seconds early: move them 2.5 later.
Why do subtitles go out of sync?
Because they were timed to a different version of the video. A longer or shorter opening puts every line out by the same amount. A different frame rate makes them drift: about 4% between 25 and 23.976 frames a second, or roughly 2.5 minutes by the end of an hour.
- Every line is out by the same amount
- Usual causeA different cut: an extra intro, a removed recap or ads
- FixShift every caption
- Fine at the start, worse and worse later
- Usual causeA different frame rate, such as 25 against 23.976 frames a second
- FixSync from two points
- Out by different amounts in different parts
- Usual causeScenes added or removed in the middle
- FixShift, then fix sections in the subtitle editor
| What you see | Usual cause | Fix |
|---|---|---|
| Every line is out by the same amount | A different cut: an extra intro, a removed recap or ads | Shift every caption |
| Fine at the start, worse and worse later | A different frame rate, such as 25 against 23.976 frames a second | Sync from two points |
| Out by different amounts in different parts | Scenes added or removed in the middle | Shift, then fix sections in the subtitle editor |
What does syncing from two points do?
It fixes a delay and a drift at once. Give the time of an early caption and a late caption in the file, and the times they should have. Every caption in between is moved and stretched in proportion, so both lines land where they belong.
Pick lines that are far apart and start cleanly, such as the first line of dialogue and one in the last scene. The boxes start out holding the file’s first and last caption times, so you only type where they should be.
What stays the same when you shift a subtitle file?
Everything except the times. Cue numbers, text, line breaks, VTT positions and notes, ASS styles and every field of their lines are written back exactly, in the same format and with the same line endings. Here is a VTT file moved 2.5 seconds later.
WEBVTT 1 00:00:11.500 --> 00:00:14.000 line:85% <v Maya Rao>Okay, shall we start with the budget?</v> 2 00:00:14.600 --> 00:00:17.900 <v Daniel Okafor>Yes. The numbers came in this morning.</v>
WEBVTT 1 00:00:14.000 --> 00:00:16.500 line:85% <v Maya Rao>Okay, shall we start with the budget?</v> 2 00:00:17.100 --> 00:00:20.400 <v Daniel Okafor>Yes. The numbers came in this morning.</v>
To change the words or single captions instead, open the file in the subtitle editor; to change its format, use the subtitle converter.
How do you get subtitles that are in sync from the start?
Time them from the recording itself. NoteOwl transcribes audio and video on your Mac with on-device AI models and saves an SRT file in which each caption starts when its words are spoken, with nothing uploaded.
FAQ
Questions about shifting subtitles
How do I fix subtitles that are out of sync?
Work out how early or late the captions are, then shift the file by that amount in NoteOwl’s subtitle shifter. If they start in sync but drift further off, sync subtitles from two points instead: one line near the start, one near the end.
Which subtitle files can I shift?
SRT, WebVTT, SBV, ASS and SSA. The shifter rewrites only the times and keeps the rest of the file exactly as it was, so VTT positions and ASS styles survive.
What happens to captions that move before 0:00?
A caption that would end before the video starts is left out, and SRT captions are renumbered so the numbers have no gaps. One that would start before 0:00 but end after it starts at 0:00.
Can I shift only part of a subtitle file?
The shifter moves the whole file. To move one section, shift the file, then open it in NoteOwl’s subtitle editor and change the times of the captions that are still off.
How precise is the shift?
To the millisecond in SRT, VTT and SBV files. ASS and SSA files store hundredths of a second, so their times are rounded to the nearest hundredth.
Is my subtitle file uploaded?
No. The shifter runs in your browser: the file is read, shifted and downloaded on your own device.
Keep exploring
More subtitle tools
- Online subtitle editorEdit an SRT or VTT file in your browser: change text and times, add and delete captions, catch overlaps and over-fast captions, download
- Subtitle mergerMerge two subtitle files in your browser: two languages stacked into bilingual captions, or two parts joined one after the other; SRT, VTT, SBV, ASS
- YouTube transcript to textPaste the transcript YouTube shows under a video and get clean paragraphs, with or without timestamps, as text, Word or SRT; nothing is fetched from YouTube
- Subtitle converterConvert subtitles between SRT, VTT, SBV and ASS, or to plain text, in your browser; SSA scripts and meeting transcripts work too
Subtitles timed from the speech, on your Mac
Free to download. Runs entirely on your Mac.
macOS 26 or later · Apple Silicon (M1 or newer) · 16 GB memory minimum, 24 GB recommended
About NoteOwl
NoteOwl is private AI meeting notes and memory for the Mac. It captures meetings without a bot joining the call, labels every speaker, writes summaries and action items, and builds a memory of every conversation that you can chat with — fully offline, because the speech recognition and the AI run on the Mac itself. Dictation into any app is free; Pro is a one-time purchase.
NoteOwl pricing: what’s free and what Pro adds
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