Convert subtitle files between popular formats instantly in your browser. No uploads, no registration required.
Subtitle files are text-based documents that contain timed text entries synchronized with video playback. Each subtitle format uses a different syntax to represent the same fundamental data: a sequence number or identifier, a time range (start and end timestamps), and the displayed text content. Our converter parses the input format's structure and re-serializes it into the target format's syntax, preserving all timing and text information.
SRT is the most widely supported subtitle format. Each entry consists of a sequential number, a timestamp line with start and end times separated by " --> " (using comma as the millisecond separator, e.g., 00:01:23,456), and one or more lines of text. Entries are separated by blank lines. SRT supports basic HTML-like tags such as <b>, <i>, and <u> for styling, though support varies by player.
WebVTT is the W3C standard for displaying timed text in HTML5 video elements. It begins with a WEBVTT header line and uses a similar structure to SRT but with periods as millisecond separators (e.g., 00:01:23.456). VTT supports optional cue identifiers, CSS-based styling through ::cue pseudo-elements, positioning directives (vertical, line, position, align), and region definitions for advanced layout control. It is the native subtitle format for web browsers.
ASS is a feature-rich subtitle format popular in anime fansub communities and advanced video editing. It uses an INI-like structure with sections: [Script Info] for metadata, [V4+ Styles] for defining named styles (font, color, size, alignment, margins), and [Events] for dialogue lines. Each dialogue line references a style and supports inline override tags like {\b1} for bold, {\c&H0000FF&} for color, and {\pos(x,y)} for positioning. ASS enables complex typesetting effects that other formats cannot represent.
The converter first detects the input format by examining structural markers: the WEBVTT header for VTT, [Script Info] for ASS, or numbered entries with comma-separated timestamps for SRT. It then parses each entry into an intermediate representation containing start time (in milliseconds), end time, and plain text content. Finally, it serializes this intermediate data into the selected output format, applying the correct timestamp syntax, structural elements, and default styling where applicable. When converting to ASS, a default style definition is generated. When converting from ASS, inline style tags are stripped to produce clean text output.
All parsing and conversion logic executes entirely within your browser's JavaScript engine. The subtitle content is processed in memory and never transmitted over the network. This ensures complete privacy regardless of the subtitle content's language or sensitivity.
Convert SRT subtitles to WebVTT for use with HTML5 <track> elements in web-based video players.
Convert between formats to match the requirements of different video editing software and media players.
Translators often receive subtitles in one format but need to deliver in another format required by the client or platform.
Prepare subtitles in the specific format required by streaming platforms like YouTube (SRT), Vimeo, or custom HLS players (VTT).
Convert plain SRT/VTT subtitles to ASS format for advanced typesetting with custom fonts, colors, and positioning effects.
