PST

Subtitle Sync Tool

Fix subtitles that drift over time. Add sync points where a subtitle timestamp should appear at a different time, then download a corrected SRT, VTT, or ASS file.

Upload subtitle file
Supports SRT, VTT, ASS, and SSA. The timing correction runs locally in your browser.
Sync points
Enter the subtitle time from the file and the time where that line should actually appear in the video.
Preview and export
Preview corrected timings, choose an output format, and download the synced subtitle file.

Sync points

0

Timeline

00:00:00,000 to 00:00:00,000

Upload a subtitle file and add valid sync points to export.

Timing preview

Showing the first 20 cues before and after sync correction.

Preview appears after you upload a subtitle file and add valid sync points.

Sync subtitles when a simple delay is not enough

Use this tool when subtitles start close to correct but become more early or late toward the end. Sync points create a timing map that retimes every cue without manual line-by-line editing.

Fix gradual drift

Use two sync points to stretch or compress subtitle timing when the offset grows over time.

Multi-point correction

Add extra anchors when different sections need different timing adjustments.

Preserve source details

When exporting the same format, timing is rewritten while VTT settings and ASS styling are kept where possible.

Export ready files

Preview corrected cues and download a synced subtitle file as SRT, VTT, or ASS.

How to resync subtitles

  1. 1

    Upload subtitles

    Choose an SRT, VTT, ASS, or SSA subtitle file from your device.

  2. 2

    Add sync points

    Enter a subtitle time and the video time where that line should appear.

  3. 3

    Download synced file

    Preview the retimed cues, choose a format, and export the corrected subtitles.

Subtitle sync examples, drift fixes, and sync point rules

Use a subtitle sync tool when captions are not off by one simple delay. Add sync points from the original subtitle timeline and the corrected video timeline, then retime every cue with a timing map.

Example input and output

Sync points
Original 00:01:00,000 -> should be 00:01:02,000 Original 00:45:00,000 -> should be 00:45:18,000
Corrected timing
1 00:01:02,000 --> 00:01:05,000 The first anchor is aligned. 482 00:45:18,000 --> 00:45:21,000 The later drift is corrected.

Best for

Fix subtitle drift

Correct subtitles that start close to synced but become gradually early or late toward the end of the video.

Repair mismatched releases

Resync subtitles from a different cut, encode, intro length, or streaming version without editing every cue manually.

Multi-section timing fixes

Use three or more sync points when one part of the video needs a different timing correction than another part.

Common file issues handled

One point shifts timing

A single sync point behaves like a delay correction and adds the same offset to all cues.

Two points fix drift

Two sync points stretch or compress the timeline between the anchors, which handles common gradual drift.

Extra points split the map

Three or more points create separate timing segments, useful when drift changes after edits or ad breaks.

Format preservation

When exporting the same format, SRT, VTT, and ASS timing lines are rewritten while source details are kept where possible.

Format compatibility guide

Use time shifting for constant delay

If every cue is exactly 2 seconds early or late, the Subtitle Time Shifter is faster.

Shift subtitle timing

Use FPS conversion for known frame rates

If you know the subtitles were timed for 25 fps and the video is 23.976 fps, FPS conversion is more direct.

Convert subtitle FPS

Use the editor for cue-level changes

Open the subtitle editor when individual lines need text edits, manual timing, insertion, or deletion.

Edit subtitles

Frequently Asked Questions

How do I fix subtitles that drift over time?
Add at least two sync points: one near the beginning and one near the end. Enter the original subtitle time and the time where that line should actually appear.
What is the difference between subtitle sync and time shifting?
Time shifting adds the same offset to every cue. This sync tool can stretch or compress timing between sync points, which helps when the offset changes over the video.
Can I use more than two sync points?
Yes. Three or more sync points create a piecewise timing map, which is useful when different parts of the video drift by different amounts.
Which subtitle formats are supported?
The tool supports SRT, WebVTT, ASS, and SSA subtitle files. You can export as SRT, VTT, or ASS.
Does this upload my subtitle file?
No. The sync correction happens locally in your browser after the page loads.