Subtitle File Converter - Online SRT ↔ VTT & Timestamp Shift

SRT (SubRip) is the oldest and most widely supported subtitle format, using commas in timestamps (00:00:01,000) and sequential numbering. VTT (WebVTT) is HTML5's standard, using periods (00:00:01.000), no numbering, and a WEBVTT header. VTT supports richer styling and is preferred for web video, while SRT is universally compatible with media players and editing tools.

Our timestamp shift operates at millisecond precision. You can shift all timestamps forward (positive values) or backward (negative values). The tool ensures no timestamp goes below 00:00:00.000. This is perfect for fixing out-of-sync subtitles — common when subtitles drift by a few seconds across a video.

Yes! Both SRT and VTT support HTML-style tags like <i>, <b>, and <u>. Our converter preserves all inline formatting tags intact. VTT-specific features like <c> (class spans) and cue settings are also retained when converting to VTT. Note that some advanced VTT features (like region definitions) may be simplified when converting to SRT.

No — everything happens locally in your browser. Your subtitle files never leave your device. We use client-side JavaScript for all parsing and conversion. This makes the tool faster, more private, and fully functional even offline.

The tool reads files as UTF-8 by default, which covers virtually all modern subtitle files. If your SRT/VTT uses a different encoding (like Windows-1252 or Shift-JIS), you may see garbled characters. In that case, re-save your file as UTF-8 using a text editor before converting. Downloaded files are always saved as UTF-8.

Absolutely! Select the "Offset Only" mode in the control bar. This shifts all timestamps by your specified amount while keeping the original format (SRT stays SRT, VTT stays VTT). It's ideal for fixing subtitle sync issues without any format conversion.

VTT files can include optional metadata like NOTE blocks, STYLE blocks, and REGION definitions. When converting VTT → SRT, these VTT-specific elements are stripped because SRT doesn't support them. When converting SRT → VTT, a clean WEBVTT header is generated. If you need to preserve VTT metadata, use the "Offset Only" mode instead.

Since processing happens in your browser, the practical limit depends on your device's memory. Most subtitle files are under 1MB (a feature-length movie's subtitles are typically ~100KB). Files up to 10MB should process smoothly. For extremely large files (100MB+), you may experience slower performance.

Yes, completely free. There are no limitations, watermarks, or registration requirements. You can use this subtitle converter for personal projects, professional video production, or any commercial workflow without restriction.