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YouTube Subtitle Timing Shifter

Move all valid SRT or WebVTT cues earlier or later and proportionally scale the timeline from video time zero.

Free browser toolRuns in your browserNo sign-up

Timeline transform

3 cues transformed

Scaling is applied from video time zero, then the offset is added. Preview representative cues against the final edit before replacing a published file.

First cue before

00:00:00,000

First cue after

00:00:01,500

Scale

100%

Clamped cues

0

Negative timestamps are clamped to zero.

00:00:01,500 → 00:00:04,700

Clear captions help viewers follow the explanation.

00:00:04,900 → 00:00:08,600

Review timing, line length and the words on screen.

00:00:08,800 → 00:00:12,300

Then upload the finished caption file with the video.

About the YouTube Subtitle Timing Shifter

YouTube Subtitle Timing Shifter applies one offset to every parsed caption cue. Positive seconds move captions later, negative seconds move them earlier, and the optional percentage scale stretches or compresses the full timeline from video time zero.

The preview compares the first timestamp before and after transformation and reports cues affected by negative-time protection. Any calculated timestamp below zero is clamped, with a minimum positive cue duration retained.

Global offset and scale corrections cannot repair individual transcription drift or edit changes. Check early, middle and late cues against the final video before replacing a caption file.

Key features

  • SRT and WebVTT parsing
  • Positive or negative global offset
  • Proportional timeline scaling
  • First-cue before-and-after comparison
  • Negative-time clamping report
  • Transformed cue preview
  • SRT or WebVTT output
  • Copy and local download

How to use

  1. 1Paste a structurally valid SRT or WebVTT caption file.
  2. 2Enter a positive offset to move captions later or a negative offset to move them earlier.
  3. 3Use timeline scale only when drift grows proportionally across the video.
  4. 4Preview representative cues, download the transformed file and verify it against the final edit.

Examples

Move captions 1.5 seconds later
Input: Valid SRT file, +1.5-second offset and 100% scale
Output: Every cue shifted later by 1.5 seconds

Verify cues near the start, middle and end of the final video.

Frequently asked questions

What does a positive offset do?
It adds time to every cue, moving all captions later.
When should I change the scale?
Use scaling only when synchronization drift grows progressively, rather than when every cue is wrong by the same amount.
What happens to negative timestamps?
They are clamped to zero and counted in the report instead of being exported as negative values.
Can this fix one incorrect cue?
The tool applies a global transform. Edit individual cues separately when only part of the file is wrong.

Continue your workflow

Open a related tool to prepare your files or refine the finished result.