What is an SRT file and how do you make one?

What is an SRT file? It is a plain text file that tells a video player which words to show and when to show them. The name stands for SubRip Subtitle, and the filename ends in .srt. It contains text and timing information, not the video or audio itself.

You might receive one alongside a video, download one from a subtitle editor, or need one for a YouTube upload. Open it in a text editor and you will see a readable pattern rather than a document full of formatting.

What is an SRT file made of?

An SRT file consists of subtitle blocks, also called cues. Each cue has a number, a start and end time, and the text that appears during that interval. A blank line separates it from the next cue.

Here is a short example:

1
00:01:02,500 --> 00:01:05,000
Open the folder
and choose your video.

2
00:01:05,200 --> 00:01:08,000
Check the subtitles before uploading.

The first cue appears one minute and two and a half seconds into the video. It disappears at one minute and five seconds. The next cue starts just after that.

Read each timestamp as hours, minutes, seconds, and milliseconds. SRT uses a comma before the milliseconds. The arrow between the timestamps separates the start time from the end time.

The number above each timestamp identifies the cue's position in the file. It is not a time or a line count. The subtitle text normally occupies one or two lines, followed by an empty line before the next numbered block.

That blank line matters. Without it, a player or upload system may have trouble recognizing where one cue ends and another begins.

What an SRT file does and does not contain

An SRT file gives you timed text that can travel separately from the video. This is often called a sidecar subtitle file. A player reads the file while playing the matching video and displays the text at the specified times.

The subtitles are not permanently drawn onto the picture. When the player supports separate subtitle tracks, you can usually turn them on or off without changing the video file.

SRT is also not a reliable way to control typography or placement. Some players recognize basic formatting, but support varies. Do not assume a font, color, or position will carry over from one player to another.

A transcript is different. It presents the words as continuous text, sometimes with timestamps for reference. An SRT breaks those words into timed pieces intended for reading while watching. Changing a transcript's filename to .srt does not create those pieces or their timings.

Where you can use SRT subtitles

SRT is widely supported, though you should always check the requirements of your destination.

• Video players such as VLC can load a separate SRT file while playing a video.
• YouTube Studio accepts SRT files when you upload subtitles for a video.
• Video editing software often imports SRT files as timed caption items that you can review on the timeline.
• Some media libraries and television players recognize a matching subtitle file stored beside the video.

For local playback, using the same base filename can help a player find the subtitles. For example, cooking-demo.mp4 and cooking-demo.srt clearly belong together. Some players load the matching file automatically, while others require you to select it from a subtitle menu.

Keep the video version in mind. An SRT timed to the original recording may no longer match after you remove an introduction or cut a section from the middle.

How to open and edit an SRT file

You can open an SRT in any plain text editor. Notepad on Windows works. On a Mac, TextEdit works when you use plain text mode rather than rich text mode.

If double-clicking opens a video player, use your computer's Open With option and choose a text editor instead. You are changing the file's contents, not playing it.

When editing, preserve the cue structure:

• Keep each cue number on its own line.
• Leave the start time, arrow, and end time together on the next line.
• Put the subtitle text below the timestamps.
• Keep an empty line between cues.

Save the file as UTF-8 so accented letters and other characters have a better chance of displaying correctly across systems. Check that the filename still ends in .srt, not .srt.txt. Some editors add a text extension unless you change the save settings.

Avoid saving through a word processor in its normal document format. A document with fonts, page margins, and other formatting is not a plain text subtitle file, even if you change its extension.

After editing, load the saved file with the video. Reading the text alone will not reveal every timing or readability problem.

How SRT differs from VTT

SRT and VTT both store timed text, but they use different syntax. VTT stands for WebVTT and is commonly used for captions in web video players.

A WebVTT file starts with the line WEBVTT, followed by a blank line. Its timestamps use a dot before the milliseconds, such as 00:01:02.500. SRT uses a comma, as in 00:01:02,500, and its usual structure includes numbered cues.

WebVTT also supports features beyond basic subtitle text, including cue positioning and other web-oriented information. Whether those features appear depends on the player and the file.

Choose the format your destination requests. If an upload field asks for SRT, supply SRT. If a web player expects VTT, use VTT. Renaming the extension alone is not a proper conversion because the contents also need to follow the destination format.

For ordinary subtitle delivery, readable text and correct timing matter more than choosing one format as universally better.

How to make an SRT file from a video

You can write an SRT manually, but you must supply both the words and the timing. For an existing recording, starting with a timed transcript saves you from building every cue from scratch.

Start with the recording

Use the final video version whenever possible. Timing subtitles before making cuts creates extra work because edits can shift everything that follows.

Kotosay is a website that turns audio and video files into text online. You can start by turning your video into text, with the language detected automatically or selected by you.

Review the words and line breaks

Check the text against the recording. Pay particular attention to names, unfamiliar terms, and small words that change the meaning of a sentence. Kotosay's free on-page editor lets you fix words while the timestamps stay.

Review how the wording will read as subtitles, not just as paragraphs. Break at a natural phrase boundary where possible. Avoid leaving an article such as “the” at the end of a line while its noun starts the next.

Kotosay's subtitle format supports up to two lines of up to 42 characters and up to 17 characters per second. Its short mode uses one line of about 20 characters. These limits guide the layout, but you should still check the result with your video.

Download and test the subtitle file

When you are ready to create the file, use Kotosay's subtitle generator. SRT and VTT downloads are available on the paid Unlimited plan.

Choose the format accepted by your player or publishing platform. Load the downloaded subtitles with the video and check the beginning, a section in the middle, and the ending. Then review any passage where the speech is dense or the wording needed correction.

Common SRT problems and what to check

Accented letters look wrong

Garbled characters often point to an encoding mismatch. Reopen the file with the correct encoding if your editor offers that option, then save it as UTF-8. If the characters have already been replaced or lost, you may need to correct the affected words before saving again.

Subtitles overlap or appear out of order

Each cue should end after it starts. For ordinary sequential subtitles, check that a cue does not extend into the next cue's display time. Overlaps can produce stacked text or inconsistent playback, depending on the player.

Keep cue numbers in sequence after inserting or deleting blocks. Also check that you have not accidentally changed a comma, arrow, or blank line.

The lines are too long to read comfortably

A subtitle can be technically valid yet difficult to follow. Long lines may wrap differently across screens, and dense text may disappear before you finish reading it.

Split text at sensible phrase boundaries and watch it at normal playback speed. Do not fix an overlong line by stretching its end time into unrelated speech. The words still need to match what is happening.

The whole file is out of sync

If every subtitle is early or late by a similar amount, check whether the video has an added opening or a missing section. If the mismatch grows as playback continues, confirm that the subtitles were made for that exact video version.

An SRT is simple to inspect, but its usefulness depends on matching the recording. Keep the structure intact, save as UTF-8, and always test the finished file where you intend to use it.