SRT vs VTT — Differences and When to Use Each

Here is the same subtitle content in both formats:

SRT version

1
00:00:00,000 --> 00:00:03,500
Welcome to the tutorial.

2
00:00:03,600 --> 00:00:07,200
Let's get started.

VTT version

WEBVTT

00:00:00.000 --> 00:00:03.500
Welcome to the tutorial.

00:00:03.600 --> 00:00:07.200
Let's get started.

Three differences are visible in this minimal example:

1. VTT requires a header. The literal string WEBVTT on line 1 followed by a blank line. SRT has no header — the file starts directly with the first cue.
2. Timecode separator differs. SRT uses a comma between seconds and milliseconds (00:00:03,500). VTT uses a period (00:00:03.500). This is a hard rule of each format — mixing them breaks parsing.
3. Cue identifiers are optional in VTT. SRT requires the leading sequence number on each cue (1, 2, 3...). VTT lets you omit them (we did, in the example above).

Beyond these visible differences, VTT supports advanced features SRT doesn't.

1. Cue settings — positioning subtitles anywhere

VTT lets you place a cue at a specific location on the video frame:

WEBVTT

00:00:00.000 --> 00:00:03.000 line:0 align:start
This appears at the top-left

00:00:04.000 --> 00:00:07.000 line:90% align:center
Standard bottom-center subtitle

SRT cues always appear in the player's default subtitle position (centered at the bottom). If you need positioning, VTT is required.

2. CSS styling via STYLE blocks

VTT supports a CSS-like styling block at the top of the file:

WEBVTT

STYLE
::cue {
  background-color: rgba(0,0,0,0.8);
  color: yellow;
  font-family: sans-serif;
  font-size: 24px;
}

00:00:00.000 --> 00:00:03.000
Custom-styled subtitle.

Some video players also accept ad-hoc HTML-like tags inside SRT cue text (<b>, <i>, <font color="...">), but these are non-standard and support is inconsistent. VTT's STYLE block is part of the W3C spec and works reliably in browsers.

3. Multiple track types

VTT can be used for content beyond captions and subtitles — chapters, audio descriptions, and arbitrary metadata cue points. The kind attribute on the HTML <track> element selects what role the file plays. SRT is essentially captions or subtitles only.

4. Comments via NOTE

VTT supports comment blocks marked with NOTE that aren't displayed:

WEBVTT

NOTE
This is a comment in the file.
Useful for documentation.

00:00:00.000 --> 00:00:03.000
Visible subtitle.

SRT has no equivalent — anything in an SRT file that looks like a comment is treated as subtitle text.

The pattern: SRT is the safer default for general-purpose video work; VTT is required only when you're working specifically with HTML5 video on the web.

Conversion is mechanical — a sequence of straightforward text substitutions.

SRT to VTT

1. Add WEBVTT as the first line of the file
2. Add a blank line after WEBVTT
3. Replace all commas in timecodes with periods (e.g., 00:00:03,500 → 00:00:03.500)
4. Save with the .vtt extension

That's it. Cue identifiers (the numbers 1, 2, 3) can stay or be removed — VTT accepts them either way.

VTT to SRT

1. Remove the WEBVTT header line and the blank line after it
2. Remove any STYLE, NOTE, or cue setting metadata
3. Replace all periods in timecodes with commas (e.g., 00:00:03.500 → 00:00:03,500)
4. Add sequence numbers if missing — start at 1, increment by 1 per cue
5. Save with the .srt extension

Tools that do this in one click

• HappyScribe Online Converter — drag-and-drop, free
• GoTranscript Subtitle Converter — multi-format, free
• Subtitle Tools — handles SRT, VTT, ASS, TXT
• Subtitle Edit (desktop, Windows) — full editor with batch conversion
• Aegisub (desktop, all platforms) — pro-grade, also converts

Doing it programmatically

If you have many files to convert, regex find-and-replace in any text editor handles SRT-to-VTT instantly. The change is just timecode separators plus the header. A 5-line Python script using re.sub can batch-convert hundreds of files.

• Wrong timecode separator. The most common error: putting commas in a VTT file or periods in an SRT file. The format spec is strict — wrong separator means the file won't parse.
• Missing WEBVTT header. A VTT file without the WEBVTT header on line 1 is invalid. Browsers fail silently — your subtitles just won't appear.
• Renaming SRT to VTT (or vice versa) without converting content. Doesn't work — the file content needs to actually be in the right format, not just have the right extension.
• Using SRT in HTML5 <track>. Browsers reject SRT as a track source. You must convert to VTT first.
• Wrong file encoding. Both formats require UTF-8. Saving as Windows-1252 or another encoding breaks non-ASCII characters (accented letters, Chinese, Arabic).
• Missing blank lines between cues. Both formats require a blank line separating cues. Some parsers fail on missing blank lines; others read everything as one giant cue.
• Inline styling that isn't supported. SRT's HTML-like tags work in some players but not all. If you need reliable styling, use VTT with a STYLE block.