Subtitle Time Shifter Online — Sync SRT and VTT
Shift every SRT or VTT subtitle cue forward or backward by an exact number of seconds directly in your browser.
Files are processed locally in your browser and are not uploaded.
About this tool
When captions consistently appear too early or too late, this tool applies one offset to every valid cue. Positive values delay subtitles, while negative values move them earlier without changing the caption text.
How to use
- Choose a supported local file or enter the required values.
- Review the available settings and run the tool.
- Check the result, then download or copy it before closing the page.
Features
- Positive and negative offsets with decimal seconds.
- Supports pasted SRT and WebVTT data or local files.
- Downloads the synchronized subtitle in its working format.
Common use cases
- Fix subtitles that start several seconds late.
- Synchronize captions after trimming an intro.
- Apply a measured delay before muxing subtitles.
Common issues and tips
- A negative shift cannot produce valid timestamps below zero.
- A single offset cannot correct subtitles that drift progressively over time.
Privacy
Your video, image or subtitle data is processed locally in your browser and is not uploaded to Tools12345.
Frequently asked questions
Which direction does a positive value move subtitles?
A positive value delays every cue.
Can it fix gradual subtitle drift?
No. Drift requires time stretching, while this tool applies one constant offset.
Is the subtitle text changed?
No. Only valid cue timestamps are shifted.