An SRT file is a plain text file used to add subtitles to videos. It’s one of the simplest and most common formats out there. If you’ve ever turned on captions on a YouTube video, there’s a good chance it was using an SRT file behind the scenes.
People use SRT files for all kinds of things: social media clips, online courses, interviews, films, you name it. They’re easy to make, easy to edit, and they work pretty much everywhere without hassle.
In this post, we’ll go over what an SRT file actually is, how it works, where it shows up, and what you should know if you’re planning to use one.
So, what does SRT mean in text? To put it simply, an SRT file is a plain text file that provides subtitles or captions to a video. The name comes from “SubRip Subtitle,” and it’s one of the most widely used formats for this purpose. So, what does "SRT" mean in text? Basically, it’s a way to tell the video player: “At this time, show this line of text.” It keeps subtitles in sync with what’s happening on screen.
Each SRT file is made up of blocks. Every block includes:
There’s no audio or video inside—it’s just text and timing. But that simplicity is a big reason why the format works pretty much everywhere: video players, editing software, social media platforms, and more. You can open and edit an SRT file using any plain text editor. That makes it easy to fix errors, update translations, or create new captions from scratch.
SRT subtitles are also a big help for accessibility. They let people who are deaf or hard of hearing follow along with video content. And they’re useful when watching something in a language you’re still learning: reading along with the audio can make it easier to understand and pick up new words.
So, SRT files are a simple, practical way to add captions that actually help people.
SRT files work by laying out subtitles in a clear, structured way. That simplicity is one of the reasons the format is so widely used: it’s easy for both people and software to read, edit, and understand.
Each SRT caption file is made up of blocks. Every block, in turn, holds a single subtitle and includes the following parts:
Each block starts with a number, starting at 1 and counting up. This just helps keep the order clear. Most video players and editors use it to track the sequence of captions.
Right after the number comes the timing which tells the player when to show the subtitle and when to hide it. The format looks like this:
00:02:17,440 --> 00:02:20,375
That means the subtitle appears at 2 minutes and 17.440 seconds, and disappears at 2 minutes and 20.375 seconds. The time format always uses hours:minutes:seconds,milliseconds.
Next comes the actual caption text. It can be one line or more. Sometimes you’ll also see extra cues like [music playing], [laughs], or [speaks Icelandic] which are there for accessibility. Some files also label speakers, like [narrator] or [man 3], to make things clearer.
Basic formatting tags are sometimes used, too. For example:
<i> for italics (used for thoughts or off-screen speech)<b> for emphasisNot all players support formatting, but many do.
After each subtitle block, there’s a blank line. That tells the video player it’s time to move on to the next subtitle.
Here’s what a simple SRT file might look like:
1
00:02:17,440 --> 00:02:20,375
Senator, we're making
our <b>final</b> approach into {u}Coruscant{/u}.
2
00:02:20,476 --> 00:02:22,501
{b}Very good, {i}Lieutenant{/i}{/b}.
3
00:02:24,948 --> 00:02:26,247 X1:201 X2:516 Y1:397 Y2:423
<font color="#fbff1c">Whose side is time on?</font>
4
00:02:36,389 --> 00:02:39,290 X1:203 X2:511 Y1:359 Y2:431
v
5
00:02:41,000 --> 00:02:43,295
[speaks Icelandic]
6
00:02:45,000 --> 00:02:48,295
[man 3] <i>♪The admiral
begins his expedition♪</i>That’s really all there is to it. With just numbers, timing, and text, SRT files keep subtitles organized and in sync with the video
SRT files support a few simple formatting options that help make subtitles clearer or add a bit of emphasis when needed. The formatting is based on basic HTML-style tags, and most players will display them as intended.
Here are some commonly used tags:
<b>…</b> or {b}…{/b} for bold<i>…</i> or {i}…{/i} for italics<u>…</u> or {u}…{/u} for underline<font color="colorname or #hexcode">…</font> to change font colorX1:… X2:… Y1:… Y2:… to adjust on-screen text position (used after the timestamp)You can also combine tags: for example, italic and color together in one line. This is called nesting, and it usually works fine across modern players.
Keep in mind that not all video platforms support formatting, and some might strip it out completely. When in doubt, test how your SRT file looks after uploading.
SRT files are plain text, but how exactly that text is saved matters a lot. If the encoding isn’t right, you might see strange characters or question marks instead of proper letters, especially in non-English subtitles.
There’s no single required encoding for SRT files, but here are the most common ones:
Out of all of these, UTF-8 is usually the safest and most reliable choice. It supports a wide range of characters, including symbols and accents, and works well across most platforms and video players.
If your SRT file includes multiple languages, special characters, or anything outside basic English text, saving it in UTF-8 will help avoid display issues.
SRT files are simple, widely supported, and easy to work with—but that simplicity also means there are some limitations. Here are a few things they can’t do:
SRT files are used in a wide range of settings where subtitles or captions are needed. Their simplicity and compatibility make them a go-to choice across different industries and platforms.
Creating an SRT file is pretty straightforward. You can write one by hand using any basic text editor, or use dedicated tools that handle the structure and timing for you. Both approaches work: just pick the one that fits your workflow.
If you want full control or just need to put something together quickly, you can create an SRT file with a plain text editor like Notepad (on Windows) or TextEdit (on Mac).
Here’s how to do it:
1 00:00:01,000 --> 00:00:04,000 This is the first subtitle. 2 00:00:05,000 --> 00:00:07,500 And this is the second.
hours:minutes:seconds,milliseconds..srt extension. For example: video-subtitles.srt.That’s it. The file is now ready to be used with most video players and platforms.
If you don’t want to do everything manually (or you’re working with longer videos) it’s easier to use subtitle tools that help with both timing and formatting. Many of these tools let you watch the video while typing captions, so you can sync things up as you go.
Here are some popular tools for creating SRT files:
SRT subtitles are simple, but getting them right takes a bit of care. These best practices can help you create captions that are clear, accurate, and easy to follow—no matter where they’re used.
SRT files are widely used because they’re simple, flexible, and work across almost every platform. Here are some of the key advantages:
The SRT file format is simple, reliable, and works almost everywhere. Whether you're adding subtitles to a short social media clip, an online course, or a full-length film, SRT files make it easy to improve accessibility and reach a wider audience.
You don’t need special tools or technical skills to get started—just a plain text editor and a bit of timing. Once you understand how SRT files work and how to create them, you’ve got everything you need to add clear, readable captions to your videos.
If you’re looking for a no-fuss way to add subtitles or translate your content, the SRT format is a solid and practical choice. Thank you for staying with me today, and until next time!
Author
Ilya is a lead of content/documentation/onboarding at Lokalise, an IT tutor and author, web developer, and ex-Microsoft/Cisco specialist. His primary programming languages are Ruby, JavaScript, Python, and Elixir. He enjoys coding, teaching people and learning new things. In his free time he writes educational posts, participates in OpenSource projects, goes in for sports and plays music.
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