Free Online Subtitle Converters — SRT, VTT, and ASS Explained

Subtitle files look simple — timestamps and text — but the format matters more than it seems. A video platform that expects WebVTT will reject a raw .srt upload, and a captioning tool built around Advanced SubStation Alpha (.ass) styling won't read either one directly.

SRT — the format almost everything starts as

SubRip (.srt) is the most common subtitle format, and the one most transcription and captioning tools export by default: a sequence number, a timestamp range, and the caption text, repeated for every line. It's simple and universally supported for playback, but it has no support for styling, positioning, or fonts.

Converting SRT to WebVTT

WebVTT (.vtt) is the format modern web video players — including HTML5 `<track>` elements — actually expect, and it's required by some platforms for uploaded caption files. The SRT ⇄ VTT Converter converts the timestamp format and header structure automatically, which otherwise means manually adjusting every timestamp's comma-to-period separator and adding a WEBVTT header by hand.

Converting to ASS for styled subtitles

Advanced SubStation Alpha (.ass) supports fonts, colors, positioning, and animation — the format fan-subbing and professional captioning tools use when subtitles need to look like more than plain white text. The SRT ⇄ ASS Converter and VTT ⇄ ASS Converter convert existing plain subtitles into an ASS shell you can then style, or strip an ASS file's styling back down to plain SRT or VTT when you just need the text and timing.

Getting a plain-text transcript

Sometimes the goal isn't another subtitle format at all — it's a readable transcript for a blog post, a summary, or a search index. The SRT ⇄ Text Converter and VTT ⇄ Text Converter strip out sequence numbers and reformat timestamps into a clean, readable list, and can convert a bracketed-timestamp transcript back into a valid subtitle file if you need to go the other way.

Common scenarios

1. A YouTuber with an auto-generated SRT transcript who needs a WebVTT file for a custom HTML5 video player.
2. A content team converting a plain SRT export into ASS so captions can match brand colors and fonts for a styled video.
3. A course creator turning lecture subtitles into a plain-text transcript to post alongside the video for accessibility and SEO.
4. A translator working from a VTT file who needs it converted to SRT because their translation tool only imports SRT.

A note on timing accuracy

Subtitle formats express timestamps differently — SRT uses commas between seconds and milliseconds, WebVTT uses periods, and ASS uses a slightly different centisecond-based layout entirely. Converting by hand means every single timestamp in the file is a chance to introduce a small error that throws captions out of sync with the audio. An automated converter applies the same transformation consistently across every line, which matters far more on a two-hour film with hundreds of cues than it does on a thirty-second clip.

Nothing leaves your browser

Every conversion happens client-side — subtitle files, which sometimes contain unreleased or confidential video content, are never uploaded anywhere.

Try them

Convert between formats with the SRT ⇄ VTT, SRT ⇄ ASS, or VTT ⇄ ASS converters, or get a readable transcript with SRT ⇄ Text or VTT ⇄ Text.