Which method should I use?

If every line is off by the same amount, use Shift. If lines start right and drift later, use Frame rate. If you are not sure, use Two points with one line near the start and one near the end.

Are my files uploaded?

No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.

Is it free? Are there limits or watermarks?

Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.

Does it work offline?

Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.

Home / Subtitles / Subtitle Shift and Sync

Subtitle Shift and Sync

Fix out-of-sync subtitles: shift all lines, correct frame rate drift, or line up two points.

Free, no uploads, no sign-up. Runs 100% in your browser.

How Subtitle Shift and Sync works

Times are moved with simple math on your device: a fixed shift, a frame rate scale, or a straight line through two reference points.

Input: SRT, VTT, ASS, SSA, SBV, SUB, LRC, SMI, TTML. Output: SRT, VTT, ASS, SSA, SBV, SUB, LRC, SMI, TTML, JSON, CSV.

How to use Subtitle Shift and Sync

Drop the subtitle file.
Pick Shift, Frame rate or Two points.
Check the new times in the table.
Download the synced file.

Tips

Nothing is uploaded. Your files stay in this browser tab.

Subtitle Shift and Sync FAQ

Which method should I use?: If every line is off by the same amount, use Shift. If lines start right and drift later, use Frame rate. If you are not sure, use Two points with one line near the start and one near the end.
Are my files uploaded?: No. This tool runs entirely in your browser tab. Files are read from your disk into memory and the result is generated locally.
Is it free? Are there limits or watermarks?: Free and open source (MIT). There are no file-size caps, daily quotas, accounts or watermarks.
Does it work offline?: Yes, once the page (and any engine it needs) has loaded, it keeps working without a connection thanks to the service worker cache.

Related tools

Subtitle Editor: Create and edit subtitles against a video preview. Set times from the player, split lines, save SRT, VTT or ASS.
Subtitle Converter: Convert between SRT, VTT, ASS, SSA, SBV, SUB, LRC, SAMI, TTML, JSON and CSV in bulk.
Extract Subtitles: Pull embedded subtitle tracks out of MKV, MP4 and MOV videos as SRT, VTT, ASS and more.
Subtitle Translator: Translate SRT, VTT or ASS files into 50+ languages on your device, keeping every timestamp.