How do I sync or shift subtitle timing forward or backward?

Upload your SRT or VTT file, enter a time shift in milliseconds or seconds (e.g. +2.5s or -1200ms), preview the retimed timestamps, and download your synchronized subtitle file.

Why are my subtitles out of sync with my video?

Out-of-sync subtitles usually happen when video releases have different intro logos, frame rates (23.976 vs 25 FPS), or cut editions. Shifting timing fixes the delay permanently.

Can I shift subtitles backward if audio plays before text?

Yes. Enter a negative value (e.g. -1.5s) to shift all cue start and end timecodes earlier.

Does the time shifter prevent negative timestamps?

Yes. Automatically clamps start timestamps to 00:00:00,000 to prevent corrupted timecodes.

Can I shift timing for a specific range of cues only?

Yes. Apply time shifting to all cues or select specific start/end cue indices.

Is processing done locally?

Yes. Subtitle timestamps are parsed and recalculated in browser JavaScript.

NexLove Media

SRT Time Shift & Subtitle Sync Adjuster

Shift all subtitle timestamps forward or backward by milliseconds or seconds to fix audio sync delay without editing lines manually.

TL;DR: SRT Time Shift & Subtitle Sync Adjuster is a 100% free browser-based media utility. Synchronize out-of-sync subtitles by shifting all timecodes forward or backward.

Drag & drop your subtitle file here

or click to browse from your device

Or press Ctrl + V to paste

SRT VTT ASS SUB Up to 20MB

100% local browser processing — this file never leaves your device

Understanding SRT Time Shift & Subtitle Sync Adjuster

Shift all subtitle timestamps forward or backward by milliseconds or seconds to fix audio sync delay without editing lines manually. Designed for creators, video editors, audio engineers, web designers, and developers who need instant, high-precision processing without software installation, watermarks, or file uploads.

Mathematical Formula & Technical Methodology

t_{\text{new}} = \max(0, \ t_{\text{orig}} + \Delta t_{\text{shift}})

Formula Variables Explained:
Adds signed time offset $\Delta t$ across all cue start and end values.

Step-by-Step Worked Example

Shifting by +1.5 seconds (+1500ms) aligns late subtitles with audio dialogue.

100% Client-Side Privacy Guarantee

All media decoding, manipulation, calculations, and encoding execute locally inside your web browser using HTML5 Canvas, Web Audio API, WebCodecs, Web Crypto, and modern JavaScript engines. Zero server uploads, zero telemetry, and no registration required.

Frequently Asked Questions

: Upload your SRT or VTT file, enter a time shift in milliseconds or seconds (e.g. +2.5s or -1200ms), preview the retimed timestamps, and download your synchronized subtitle file.
: Out-of-sync subtitles usually happen when video releases have different intro logos, frame rates (23.976 vs 25 FPS), or cut editions. Shifting timing fixes the delay permanently.
: Yes. Enter a negative value (e.g. -1.5s) to shift all cue start and end timecodes earlier.
: Yes. Automatically clamps start timestamps to 00:00:00,000 to prevent corrupted timecodes.
: Yes. Apply time shifting to all cues or select specific start/end cue indices.
: Yes. Subtitle timestamps are parsed and recalculated in browser JavaScript.

Embed This Tool

Add the live SRT Time Shift & Subtitle Sync Adjuster to your own website with this embed code:

<iframe src="https://nexlove.org/embed/srt-time-shift.html" width="100%" height="650" style="border:1px solid #e2e8f0;border-radius:12px" title="SRT Time Shift & Subtitle Sync Adjuster — NexLove" loading="lazy"></iframe>

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