WebVTT Subtitle Validator - Online Check Syntax
Paste a WebVTT file and instantly check for syntax errors. Validate timestamps and cue formatting. Essential for video devs.
UD5 Toolkit
Convert SRT subtitle files to WebVTT format instantly — paste, upload, or drag & drop
Drag & drop .srt file here
or click to browse00:00:01,000).
WebVTT (Web Video Text Tracks) is the W3C standard for HTML5 video subtitles. The key difference is WebVTT uses periods for milliseconds (00:00:01.000), requires an optional WEBVTT header, and supports styling via CSS. WebVTT is natively supported by all modern browsers for HTML5 <video> elements.
<track> element, WebVTT is the recommended and most compatible format. Converting SRT to WebVTT ensures your subtitles work seamlessly across all modern browsers and platforms.
WEBVTT header is required for a valid WebVTT file. While some players may work without it, including the header ensures maximum compatibility. Our tool includes it by default, but you can toggle it off if your specific use case doesn't require it. We recommend keeping it enabled for standards compliance.
<b>, <i>, <u>, and <span> with CSS classes. If your SRT file contains these tags, they will be preserved during conversion. Additionally, WebVTT supports <c> tags for semantic voice labeling and CSS-based styling via ::cue() selectors, offering much more flexibility than SRT.
WEBVTT header. While this tool focuses on SRT → WebVTT conversion, the process is fully reversible. Many online tools offer bidirectional conversion. The main thing to watch for is that WebVTT-specific features (like CSS styling, regions, or comments) may not translate back to plain SRT.
Paste a WebVTT file and instantly check for syntax errors. Validate timestamps and cue formatting. Essential for video devs.
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