How to sync subtitles
- Drop your .srt or .vtt file on the box above, or paste the text. A short sample is already loaded so you can try it first.
- Play the video and note how far off the subtitles are. If a line appears 1.5 seconds after it is spoken, the subtitles are late: type -1.5. If they appear too early, type a positive number.
- Leave the starting caption at 1 to move the whole file, or type a later number to move only the captions from there on, for example after a commercial break or a cut scene.
- Check the preview, then Download. The file keeps its format and gets "-shifted" added to its name.
The file is read by your browser and never uploaded, so it works for unreleased projects and private videos too.
Late or early: which sign to use
Think of the number as how much later each caption should appear. Subtitles that arrive after the voice need to come earlier, so the number is negative. Subtitles that arrive before the voice need to come later, so it is positive. Half a second is usually easy to see; for fine tuning, try steps of 0.1 seconds.
Captions that would move before the very start of the video are removed, and the result tells you how many.
When shifting is not enough
If the first lines are right after shifting but later lines slowly fall out of sync again, the problem is drift, not an offset. It usually means the subtitles were made for a version of the video with a different frame rate, such as 23.976 subtitles on a 25 fps release, where the error grows to almost 25 seconds after ten minutes. The subtitle frame rate converter fixes that, either from the two frame rates or from two captions whose right times you know.
SRT and WebVTT
The tool reads both formats and writes the one you gave it. SRT numbers its captions and uses a comma before the milliseconds (00:01:02,500); WebVTT starts with the word WEBVTT and uses a full stop (00:01:02.500). Styling such as italics, WebVTT cue settings and STYLE blocks are kept. To change format, use the SRT to VTT converter.
Subtitles from a speech-to-text tool often need more than a timing fix: the AI subtitle cleaner shortens long lines and fixes overlaps.
Questions
How do I fix subtitles that are out of sync?
Load the .srt or .vtt file, type how many seconds the captions should move (a minus number if they appear too late), check the preview and download the fixed file.
My subtitles start in sync and slowly drift. What do I do?
That is a frame rate mismatch, not an offset. Use the subtitle frame rate converter, from the two frame rates or from two captions whose correct times you know.
Is my subtitle file uploaded?
No. The file is read and changed by your browser and never leaves your device.
Can I shift only part of the subtitles?
Yes. Type the number of the first caption to move; captions before it stay where they are.