How to Create an SRT Subtitle File for Video

What an SRT file is and why you need one

An SRT file is a plain text document that holds subtitles or captions for a video. It contains the words that appear on screen, the exact timing for when each line shows up and disappears, and nothing else — no formatting, no images, no video data. Video players like VLC, Windows Media Player, and most streaming software read SRT files and display the text on top of your video at the right moments.

You create an SRT file when you want subtitles for a video you own or made, but the video file itself doesn't have them built in. You might need subtitles for a home video, a training recording, a foreign-language film, or content you're uploading to a platform that accepts separate subtitle files. Once you create the SRT file and save it with the same name as your video file (just with a .srt extension instead of .mp4 or .mov), most players will find it automatically and display the subtitles.

Key Takeaways

An SRT file is a text document containing subtitle text, timings, and sequence numbers in a specific format that any video player can read.
You can create an SRT file in any text editor — Notepad on Windows, TextEdit on Mac, or any free editor — as long as you save it as plain text with the .srt extension.
Each subtitle entry needs a sequence number, a start and end time in the format HH:MM:SS,mmm, the subtitle text, and a blank line between entries.
The easiest method for longer videos is to use free subtitle software like Subtitle Edit or Aegisub, which lets you play the video and click to set timing instead of calculating it by hand.
Save your SRT file in the same folder as your video and give it the exact same filename (except for the extension) so your player finds it automatically.

Creating an SRT file by hand in a text editor

Open Notepad (Windows), TextEdit (Mac), or any plain text editor. Do not use Microsoft Word or Google Docs — they add invisible formatting that breaks SRT files. Type your subtitles in this exact structure: a number, a line break, the start time and end time separated by an arrow, a line break, the subtitle text, and then a blank line before the next entry.

Here is what the first few lines look like:

1 00:00:05,000 --> 00:00:10,000 Welcome to the video 2 00:00:10,500 --> 00:00:15,000 This is the second subtitle 3 00:00:15,500 --> 00:00:20,000 And this is the third one

The timing format is hours:minutes:seconds,milliseconds. The comma before milliseconds is required — do not use a period. If your video is 30 minutes long and a subtitle appears at the 5-minute mark, you write 00:05:00,000. If it appears 5 seconds and 500 milliseconds into the video, you write 00:00:05,500. The end time should be when the subtitle disappears, usually a few seconds after it appears.

When you finish typing all your subtitles, save the file. On Windows, choose File > Save As, set the file type to "All Files", and type your filename with .srt at the end — for example, myvideo.srt. On Mac, use File > Save, uncheck "Use smart quotes", and add .srt to the filename. Make sure you save it as UTF-8 encoding if your text editor asks.

Using subtitle software to set timing automatically

For videos longer than a few minutes, hand-timing every subtitle is slow and error-prone. Free software like Subtitle Edit (Windows and Linux) or Aegisub (Windows, Mac, and Linux) lets you load your video, play it, and click a button to mark when each subtitle starts and ends. The software calculates the exact timing for you.

read and install Subtitle Edit from its official website. Open the program, go to File > Open Video File, and select your video. The video will play in a window on the left. Type your first subtitle text in the text box at the bottom. When you reach the moment the subtitle should appear, click the "Set Start Time" button. When you reach the moment it should disappear, click "Set End Time". The software fills in the exact timing. Press Enter or click a button to move to the next subtitle and repeat.

When you finish all your subtitles, go to File > Save Subtitle File and choose SRT as the format. The software creates the properly formatted SRT file automatically. This method is much faster than calculating times by hand, especially for videos with many subtitles.

Matching your SRT filename to your video file

Your video player finds the SRT file automatically only if the filename matches exactly. If your video is called "birthday_party.mp4", your subtitle file must be called "birthday_party.srt" — same name, different extension. If your video is "training_video.mov", the subtitle file is "training_video.srt".

Both files must be in the same folder. Put them on your desktop together, or in the same folder in your Documents, or on the same USB drive. When you open the video file in a player like VLC or Windows Media Player, the player looks in that same folder for an SRT file with the matching name and loads it automatically. If the names don't match or the files are in different folders, the player won't find the subtitles.

If your video has multiple audio tracks or versions, you can create multiple SRT files with slightly different names. For example, "birthday_party.srt" for English and "birthday_party.es.srt" for Spanish. Some players recognize the language code and let you choose which subtitle file to load.

Fixing common mistakes in SRT files

The most common error is using the wrong time format. The format must be HH:MM:SS,mmm with a comma before milliseconds, not a period. 00:05:30.500 is wrong; 00:05:30,500 is correct. If your times are formatted wrong, the player either won't load the file or will display subtitles at the wrong moments.

Another mistake is saving the file as .txt instead of .srt. Windows hides file extensions by default, so you might think you saved "myvideo.srt" when you actually saved "myvideo.srt.txt". To fix this, open File Explorer, go to View, and turn on "File name extensions". Then right-click the file, choose Rename, and remove the .txt so only .srt remains.

If you use a word processor like Word instead of a plain text editor, the file will contain hidden formatting codes that break the SRT format. Always use Notepad, TextEdit, or a dedicated text editor. If you accidentally created an SRT file in Word, open it in Notepad, copy all the text, create a new file in Notepad, paste the text, and save it as plain text with the .srt extension.

Testing your SRT file with your video

Before you share your video or upload it anywhere, test the subtitles. Open your video file in VLC Media Player (free, works on Windows, Mac, and Linux). If the SRT file is in the same folder with the matching name, VLC loads it automatically and displays the subtitles. Play through a few sections and check that the text appears at the right time and disappears when it should.

If the subtitles don't appear, check three things: the filename matches exactly (including capitalization on Mac and Linux), both files are in the same folder, and the file extension is actually .srt and not .srt.txt. If the subtitles appear but the timing is off, open the SRT file in your text editor and adjust the start and end times. Subtract a few hundred milliseconds if subtitles appear too late, or add them if subtitles appear too early.

Some video players have a subtitle offset feature that lets you shift all subtitles earlier or later without editing the file. VLC has this under Tools > Preferences > Subtitles. But it's better to fix the SRT file itself so the subtitles work correctly in any player.

Frequently Asked Questions

Can I use an SRT file with a video I upload to YouTube or another platform?

YouTube, Vimeo, and most video platforms accept SRT files as uploads. You usually upload the video file and the SRT file separately through the platform's subtitle or caption section. The platform then displays your subtitles to viewers. Check your platform's documentation for the exact upload process, as each one is slightly different.

What if my video is in a format like .mov or .mkv instead of .mp4?

The SRT file works with any video format as long as the filename matches. A .mov file called "myvideo.mov" pairs with "myvideo.srt". A .mkv file called "myvideo.mkv" pairs with "myvideo.srt". The video format doesn't matter — only the filename and the .srt extension.

Can I edit an SRT file after I create it?

Yes. Open the SRT file in any text editor, make your changes, and save it. You can fix typos, adjust timing, add or remove subtitles, or change the text. Just keep the format the same: sequence number, timing line, text, blank line. Save it as plain text with the .srt extension.

What if I have subtitles in multiple languages?

Create a separate SRT file for each language. Name them "myvideo.srt" for English, "myvideo.es.srt" for Spanish, "myvideo.fr.srt" for French, and so on. Put all of them in the same folder as the video. Some players let you choose which language to display; others load the first one they find.

Is there a limit to how many subtitles I can have in one SRT file?

No. An SRT file can contain hundreds or thousands of subtitle entries. The only limit is the size of the text file itself, which is tiny — even a two-hour movie with subtitles every few seconds creates a file smaller than 1 megabyte.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.