What is an SRT File? Everything You Need to Know

An SRT file (SubRip Subtitle) is a plain-text file that stores timed subtitle cues. It is widely supported, but not every platform or device exposes direct SRT import. An SRT contains numbered entries with a start time, end time, and display text. You can create one manually or generate an editable draft with a transcription tool such as Captain Transcribe.

What is an SRT File?

An SRT file (SubRip Subtitle file) is a plain-text file containing subtitle information for a video. Many players, editors, and publishing services support it, subject to their current import rules. The extension is .srt, and the contents can be opened in a text editor.

SRT files were originally created for the SubRip software, a tool that extracted subtitles from DVDs. The format caught on because of its simplicity. An SRT file contains nothing but numbered subtitle entries, timestamps, and text. No complex encoding, no proprietary formatting — just straightforward, human-readable data.

How Is an SRT File Structured?

Every SRT file follows the same simple structure. Each subtitle entry consists of three parts:

Sequence number — A counter that identifies the subtitle entry (1, 2, 3, and so on).
Timestamp line — The start and end time for when the subtitle should appear on screen, in the format HH:MM:SS,mmm --> HH:MM:SS,mmm (hours, minutes, seconds, milliseconds).
Subtitle text — The actual text to display. This can be one or two lines.

Each entry is separated by a blank line. Here is what a real SRT file looks like:

1
00:00:00,500 --> 00:00:03,200
Welcome to our channel.

2
00:00:03,800 --> 00:00:07,100
Today we are covering everything
you need to know about SRT files.

3
00:00:07,800 --> 00:00:11,400
Let us start with the basics.

Notice that the timestamp uses a comma as the decimal separator (not a period). This is one of the defining characteristics of SRT and a common source of errors when people try to create SRT files manually.

How to Create an SRT File

There are three main ways to create an SRT file:

Method 1: Generate an AI Draft

An AI-powered tool such as Captain Transcribe can generate an editable SRT draft from a supported video or audio file. Select the language, review the words and timestamps after processing, then export the standards-formatted file.

Method 2: Create Manually in a Text Editor

You can create an SRT file in Notepad, TextEdit, VS Code, or another plain-text editor. Type each entry using a sequence number, timestamp line, subtitle text, and separating blank line. Save it with the .srt extension and UTF-8 encoding. Manual timing and review can take substantial time; the effort varies with speech density, audio quality, and the required editorial standard.

Method 3: Use a Subtitle Editor

Subtitle editing software like Subtitle Edit, Aegisub, or Jubler lets you load a video and add subtitle entries with a visual timeline. These tools make manual timing easier than a plain text editor but still require significant time investment. They are most useful for editing an existing SRT file rather than creating one from scratch.

How to Use SRT Files with Your Videos

Once you have an SRT file, here is where and how to use it:

YouTube — YouTube currently lists basic UTF-8 SRT files. Follow the current YouTube Studio upload instructions and preview the result.
Video editors — Many desktop and web editors import SRT, but menu paths and supported variants differ. For example, CapCut documents direct SRT import on Desktop/Web but not Mobile.
Social platforms — Check the current help page for the exact account type, publishing surface, country, and device. If external subtitle import is unavailable, use a supported editor or the platform's caption workflow.
Media players — Players such as VLC can load SRT tracks. Filename-based automatic loading and rendering behavior depend on player settings.
Websites — While the web-native subtitle format is WebVTT, many web video players also support SRT. If your player requires VTT, converting from SRT is straightforward — the main change is replacing commas with periods in timestamps and adding a "WEBVTT" header.

How Does SRT Compare to Other Subtitle Formats?

SRT is not the only subtitle format. Its plain structure gives it broad support, while the destination's current documentation remains authoritative:

SRT vs VTT (WebVTT) — VTT is the web-native format and supports CSS styling and positioning. SRT is more widely supported across desktop software and social platforms. Read our detailed SRT vs VTT comparison for a full breakdown.
SRT vs ASS/SSA — ASS (Advanced SubStation Alpha) supports rich styling including fonts, colors, animations, and positioning. It is popular in anime fansubbing communities but overkill for most video creators and not widely supported outside media players.
SRT vs SBV — SBV is YouTube's legacy subtitle format. It is similar to SRT but without sequence numbers. YouTube supports both, but SRT is the standard choice.

How Captain Transcribe Generates SRT Files

Captain Transcribe can generate an SRT draft from a completed transcription. Its words and timings remain editable and must be reviewed. Three styles affect text segmentation:

Standard — Full sentences, ideal for YouTube and professional video. Each SRT entry contains a complete thought.
Short — Brief groups of up to four words for compact captions.
Word-by-word — One timed word per cue for granular editing; highlighting is configured in the destination editor.

All three styles export UTF-8 SRT files with sequence numbers and the current editable timings. Review syntax and rendering in the destination tool. TXT and VTT can be downloaded from the same completed transcription without running speech recognition again.

Key Takeaways

An SRT is a plain-text subtitle file containing numbered entries, timestamps, and text.
SRT is widely supported, but direct import varies by platform, product version, and device.
An AI tool can create an editable first draft; words, timing, speaker cues, and destination rendering still need review.
SRT uses a comma as the decimal separator in timestamps (00:00:01,500), which is the most common source of errors when creating files manually.
For an HTML <track> workflow, use WebVTT; otherwise choose a format explicitly listed by the destination.

This article was drafted with AI assistance and reviewed by The Captain before publication.