What Is an SRT File?
An SRT file (SubRip Subtitle, .srt) is a plain-text subtitle file. Each subtitle is a numbered cue with a start and end time and one or two lines of text. Players and platforms show the text over the video at those times, and viewers can switch it on or off.
1
00:00:01,000 --> 00:00:04,000
Welcome back to the show.
2
00:00:04,200 --> 00:00:07,500
Today we're talking about
subtitles for short videos.
3
00:00:08,000 --> 00:00:10,250
<i>(upbeat music)</i>How an SRT file is built
Every cue has three parts: a number, a time range written as 00:00:01,000 --> 00:00:04,000, and the text. A blank line separates cues. Milliseconds come after a comma, not a full stop — the most common reason a hand-edited SRT file fails to load.
The timestamp format
Each time line reads 00:01:02,500 --> 00:01:05,000: hours, minutes and seconds with two digits each, a comma, three digits of milliseconds, and an arrow with a space on each side. Hours are never left out, even in a 2-minute clip. A full stop instead of the comma, or a missing space around the arrow, is what makes strict players skip the cue.
Rules a valid SRT file follows
Cues are numbered 1, 2, 3 in order and sorted by start time. Exactly one blank line separates cues — without it, the next cue is read as more text of the one above. The text sits on the lines straight after the time line, usually one or two lines of up to about 42 characters. The file is saved as plain text in UTF-8.
Formatting inside the text
SRT has no styling of its own. Most players understand <i>, <b> and <u> for italic, bold and underline, and some read <font color="#ffff00">. There is no standard way to move a subtitle to the top of the screen, so positioning needs VTT or ASS, or burning the subtitles into the video.
Where SRT files are used
SRT is the format almost everything accepts: YouTube, Facebook and LinkedIn uploads, Premiere Pro, DaVinci Resolve, VLC and most TV media players. It carries no styling beyond italic, bold and underline tags, which is why it travels so well.
Opening and editing one
Any text editor opens an SRT file. Save it as UTF-8: files in older encodings turn accented letters into broken characters. To play subtitles with a video in VLC, give the SRT the same name as the video and keep them in one folder.
Questions
Is an SRT file the same as a transcript?
No. An SRT file splits speech into short timed lines for the screen. A transcript is continuous text, often with speaker names and paragraphs.
Can an SRT file change font or colour?
Only through <font> tags, which many players ignore. For real styling use ASS, or burn the subtitles into the video.
Why does my SRT file show strange characters?
It was saved in an older encoding. Re-save it as UTF-8 in a text editor.
What does an SRT timestamp look like?
00:00:04,200 --> 00:00:07,500: hours, minutes, seconds, a comma and three digits of milliseconds, then the end time in the same form.
Do SRT cue numbers have to be in order?
They should run 1, 2, 3 without gaps. Most players cope with gaps, but some upload forms reject the file, and any editor that saves SRT renumbers it.
How many characters fit on an SRT line?
The format sets no limit. Subtitle style guides such as Netflix’s keep English lines to 42 characters and captions to two lines.
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