What Is an SRT File? How to Open, Edit, Create, and Convert One

If you've ever downloaded subtitles from the internet, extracted captions from a video, or uploaded subtitles to YouTube, you've probably encountered an SRT file. It's the most widely used subtitle format in the world — and once you understand how it works, it's surprisingly simple.

What Is an SRT File?

An SRT file (SubRip Subtitle file) is a plain-text file with the .srt extension that stores timed subtitle captions for a video. The format was originally created by the SubRip software, which extracted subtitles from DVDs, and has since become the universal standard for subtitles across virtually every video platform and player.

SRT files contain no video, audio, or styling information — they are purely text with timestamps. This makes them small, portable, and easy to edit with any text editor.

SRT File Format Explained

Each subtitle entry in an SRT file follows the same structure:

[sequence number]
[start time] --> [end time]
[subtitle text]
[blank line]

Here is a real example:

1
00:00:01,000 --> 00:00:03,500
Hello, and welcome to the video.

2
00:00:04,200 --> 00:00:07,800
Today we're going to explain
how SRT files work.

3
00:00:08,500 --> 00:00:11,000
Let's get started.

Sequence number — A sequential integer starting at 1. Used to identify each subtitle cue.

Timestamps — Written as HH:MM:SS,mmm (hours, minutes, seconds, milliseconds). The comma before milliseconds is part of the SRT standard — some tools use a period instead, which can cause compatibility issues.

Subtitle text — One or more lines of text. A blank line separates each entry.

That's the entire format. There are no headers, no metadata, and no binary data — just these repeating blocks.

How to Open an SRT File

Because SRT files are plain text, you can open them with any text editor:

• Windows — Notepad, Notepad++, VS Code
• macOS — TextEdit (in plain text mode), VS Code
• Linux — gedit, nano, VS Code

To open in Notepad on Windows: right-click the file → Open with → Notepad.

Important: Always open and save SRT files in UTF-8 encoding (without BOM). Saving in a different encoding — such as ANSI or UTF-16 — will cause garbled characters for any non-ASCII text (Chinese, Arabic, Japanese, accented Latin characters, etc.).

How to Edit an SRT File

You can edit an SRT file directly in any text editor. Common edits include:

Fixing subtitle timing

If subtitles appear too early or too late, you need to adjust the timestamps. For small offsets, you can manually add or subtract time from the start and end values. For large offsets or systematic drift, a dedicated subtitle editor tool is more efficient.

Correcting text errors

Simply find the cue, edit the text, and save. Make sure not to accidentally delete or modify a timestamp line.

Adding or removing cues

To add a new cue, insert a new block with the correct sequence number, a time range, and text. After adding or removing cues, renumber the sequence numbers so they remain sequential — some video players require this.

Splitting or merging cues

If a subtitle cue contains too much text for one screen, split it into two cues with adjusted timestamps. If two consecutive cues contain fragments of the same sentence, merge them into one.

How to Create an SRT File from Scratch

You can create an SRT file manually using any text editor:

1. Open a new file in your text editor
2. Type the first sequence number: 1
3. On the next line, type the time range: 00:00:01,000 --> 00:00:03,500
4. On the next line(s), type the subtitle text
5. Leave a blank line, then repeat for the next cue
6. Save the file with the .srt extension in UTF-8 encoding

For longer videos, manually writing timestamps is tedious. A faster method is to use an audio transcription tool that generates the SRT file automatically.

Pancake Subtitle Tools' Audio to Subtitle tool uses OpenAI Whisper to transcribe audio and generate a complete SRT file with accurate timestamps. You upload the audio or video file, and the tool produces a ready-to-use .srt file in seconds.

How to Convert SRT to Other Formats

SRT is the most compatible subtitle format, but some workflows require other formats:

SRT to VTT

WebVTT (.vtt) is the subtitle format used by HTML5 video players and many streaming platforms. The structure is nearly identical to SRT:

• Replace WEBVTT at the top of the file
• Replace commas with periods in timestamps (00:00:01,000 → 00:00:01.000)

Most video tools and online converters can handle this automatically.

SRT to ASS / SSA

ASS (Advanced SubStation Alpha) is a more feature-rich format that supports custom fonts, colors, and positioning. It's commonly used in anime fansubs. Converting SRT to ASS adds default styling while preserving the text and timing.

SRT to plain text

To extract just the text without timestamps (for reading a transcript, for example), open the SRT file in a text editor and manually delete the timestamp and sequence number lines, or use a script.

Common SRT File Problems and How to Fix Them

Subtitles appear garbled (question marks or boxes instead of text) The file was saved in the wrong encoding. Open it in a text editor, change the encoding to UTF-8, and save.

Subtitles are out of sync with the video The timestamps are offset from the actual speech. Use a subtitle editor to shift all timestamps forward or backward by a fixed amount.

Subtitles don't appear in the video player Check that the .srt file has the same name as the video file (e.g., movie.mp4 and movie.srt) and is in the same folder. Most players load external subtitles automatically when the names match.

Blank lines inside subtitle text break the parsing An accidental blank line inside a cue block terminates that cue early. Remove the blank line so the text reads as a single block.

Sequence numbers are out of order Some strict parsers require sequential numbering. After adding or removing cues, renumber them sequentially starting from 1.

SRT vs VTT: Which Should You Use?

	SRT	VTT
Extension	.srt	.vtt
Compatibility	Universal	Web / HTML5
Styling support	Basic (bold, italic)	Extended (CSS)
Timestamp format	HH:MM:SS,mmm	HH:MM:SS.mmm
Header required	No	Yes (WEBVTT)

For most use cases — adding subtitles to a video for distribution, uploading to YouTube or Vimeo, or downloading subtitles for offline use — SRT is the right choice. Use VTT when building a web video player or when a platform specifically requires it.

Summary

An SRT file is a plain-text subtitle file containing timed text cues. It's the most widely supported subtitle format across video players, editing software, and streaming platforms. You can open and edit SRT files with any text editor, create them manually, or generate them automatically from audio using AI transcription.

If you need to translate an existing SRT file, the Subtitle Translation Tool can translate to 20+ languages while preserving all timestamps. If you need to create an SRT file from audio or video, the Audio to Subtitle Tool uses Whisper AI to generate accurate subtitles automatically.