SRT vs VTT vs ASS: Which Subtitle Format Should You Use?

Most subtitle files you will meet are SRT, VTT or ASS. They all store the same basic thing, text with a start and end time, but they differ in what players support and how much styling they allow. Here is what each one is good at.

SRT (SubRip): the universal choice

SRT is the simplest and most widely supported format. Each cue has a number, a time range with a comma before the milliseconds, and the text:

1
00:00:01,000 --> 00:00:03,500
Hello, and welcome back!

2
00:00:04,000 --> 00:00:06,200
Today we are making bread.

Use SRT when you want a file that simply works: VLC, Plex, Jellyfin, Kodi, Premiere Pro, DaVinci Resolve, most smart TVs and YouTube Studio all accept it. It only supports basic italics and bold.

WebVTT: subtitles for the web

WebVTT (.vtt) looks a lot like SRT, but starts with a WEBVTT header and uses a dot before the milliseconds:

WEBVTT

00:00:01.000 --> 00:00:03.500 line:10%
Hello, and welcome back!

Use VTT when you publish video on a website. It is the format of the HTML5 <track> element and of HLS streaming, and it can position cues on screen. Many streaming sites deliver their subtitles as VTT, often split into small segments.

ASS (Advanced SubStation Alpha): full styling

ASS files carry styles: fonts, colours, outlines, positions and even karaoke effects. Anime fansubs use it for typesetting. Because each line can have its own style, ASS is also the best way to show two languages at once, one at the top and one at the bottom.

[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:01.00,0:00:03.50,Bottom,,0,0,0,,Hello, and welcome back!
Dialogue: 0,0:00:01.00,0:00:03.50,Top,,0,0,0,,Bonjour et bon retour !

Use ASS when you want styling or dual subtitles and your player supports it. VLC, mpv, MPC-HC and most anime players do; many TVs and web players don’t.

Quick comparison

• Compatibility: SRT is best, then VTT, then ASS.
• Styling and positioning: ASS is best, VTT has some, SRT has almost none.
• Websites and streaming: VTT.
• Two languages on screen: ASS.
• Just the text: export TXT instead of a subtitle format.

How to convert between formats

You don’t need to install anything. Drop your files into the free online subtitle converter and choose SRT, VTT, ASS or TXT. It runs entirely in your browser, so your files never leave your computer, and it can shift timing and remove SDH notes at the same time.