Tool Subtitle Sync Shift
Fast, accurate and free online tool subtitle sync shift tool running directly in your browser.
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1Enter data
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2Click the button
The tool will immediately process your data in the browser. -
3Get the result
Copy the finished text or save the file to your device.
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Other tools you may find usefulSubtitle Sync Shift - Sync Movie Subtitles SRT
Subtitle Sync Shiftallows you to shift movie subtitles by any number of milliseconds - forward or backward. Upload an SRT or VTT file, set the offset and download the synchronized subtitle file. Work happens locally - your files are not sent to the server.
What are SRT subtitles and how do they work?
SRT (SubRip Text) is the most popular subtitle file format. Each entry contains: sequence number (1, 2, 3...), start and end timestamp in the format HH:MM:SS,mmm --> HH:MM:SS,mmm, string text (one or two lines). Example:1, 00:01:23,456 --> 00:01:26,789, Hello, dear viewer!. Subtitles are synchronized with the audio or video track - when the video file has a different delay than the original (e.g. different version, different cdr), the subtitles "do not match".
Why are the subtitles out of sync?
The most common causes of subtitle desynchronization: different versions of the video file (theatrical vs. extended vs. director's cut), different video and subtitle sources (video on one side, subtitles on the other), format conversion (from DVD to MP4, from TS to MKV), interlacing and frame rate mismatch (23.976 vs. 24 vs. 25 fps), adding or removing fragments (intro/outro) on streaming platforms), manually created subtitles with synchronization errors.
How to use the tool?
Step 1: upload the SRT or VTT file via drag & drop or the "Upload" button. Step 2: remove offset in milliseconds - positive moves subtitles forward (subtitles appear later), negative moves subtitles backward (subtitles appear earlier). Example: "The subtitles are 2 seconds too late" → offset = -2000 ms. "Subtitles appear 1.5 seconds too early" → offset = +1500 ms. Step 3: Preview - You can see several entries after correction. Step 4: Download the file.
Other subtitle formats
In addition to SRT, the tool supports:VTT (WebVTT)- the HTML5 video standard used by YouTube.ASS/SSA- Advanced format with positioning and font style (used in anime).SBV- YouTube format.SUB/IDX- image subtitles (not text, not supported by a text editor).Embedded subtitles- in MKV files (track subtitles) - extract them first via MKVToolNix or FFmpeg before editing.
Frequently asked questions
How to check how many milliseconds the subtitles are shifted?
Method: stop the video at a clear sentence, check the time in the video player, compare with the timestamp in the SRT file (open in notepad). Difference = offset. Example: spoken dialogue at 00:05:23, but subtitle appears at 00:05:25 → subtitles are +2000 ms too late → correct -2000 ms. Alternatively: programs like Aegisub have a visual interface for calibration by marking synchronization points.
How to edit SRT subtitles in notepad?
An SRT file is plain text - open in Notepad, VS Code, Notepad++. Each entry: number, blank line, timestamp, text, blank line. To edit one timestamp: change manually. To change all: Ctrl+H (Replace) - but it's hard for milliseconds. Subtitle Sync Shift tool automatically recalculates all timestamps with one click.
How to extract subtitles from MKV file?
MKVToolNix (Windows/Mac/Linux) - GUI: Multiplexer → open MKV → Tracks → select subtitle track → Extract. Or FFmpeg (command line):ffmpeg -i film.mkv -map 0:s:0 subtitles.srt(extracts the first subtitle track). Once extracted, you can edit the SRT file via the Subtitle Sync Shift tool.
Does the tool work with multilingual subtitles?
Yes - the SRT file is encoded in UTF-8 (standard for multilingual subtitles). The tool only modifies timestamps, not text, so all languages (Arabic, Chinese, Cyrillic, Polish characters) are preserved unchanged. If the file is in an older encoding (Windows-1250, ISO-8859-2), it may require conversion to UTF-8 before uploading (use Notepad++ → Encoding → Convert to UTF-8).
What programs allow advanced editing of subtitles?
For a simple offset: our online tool. For advanced editing: Aegisub (free, Windows/Mac/Linux) - professional tool with visual synchronization, style editing and typesetting. Subtitle Edit (Windows) - comprehensive editor, error detection, synchronization via audio fingerprint. Jubler (Java, cross-platform) - SRT/SSA/SMI editor. FFmpeg with asetpts/subtitles filter - advanced conversion and synchronization via CLI.