SRT vs VTT vs ASS: which subtitle format should you use?

SRT — the one that works almost everywhere

SubRip (.srt) is the simplest format: a number, a time range, and the text. It carries no styling beyond a few basic tags that not every player honours. That simplicity is exactly why it is accepted nearly everywhere — YouTube, Facebook, video editors, media players and most online platforms.

If you are not sure which format to use, use SRT.

VTT — made for web video

WebVTT (.vtt) is the subtitle format of HTML5 video. It looks much like SRT but adds a WEBVTT header, uses a dot instead of a comma in timestamps, and supports cue settings for position and alignment plus a basic styling layer.

Use VTT when the captions are going into a video player on a web page through the HTML <track> element.

ASS — when the look matters

Advanced SubStation Alpha (.ass) supports fonts, colours, outlines, shadows, exact positioning and effects. It is popular for anime fansubs and anywhere captions are part of the design.

That power comes with narrower support: many platforms will not accept ASS uploads. It is most often used as the source for burning styled subtitles into the video itself — which is how SubFlow renders burned-in captions.

Which one to choose

Pick by where the subtitles are going:

• YouTube, Facebook, LinkedIn or a video editor: SRT.
• A video player on your own website: VTT.
• Styled captions that must look exactly right: burn them into the video.
• Just the words, for notes or a blog post: a plain-text transcript.

Questions