Creating subtitles: SRT or VTT, and how to get them onto YouTube
October 21, 2026 · 6 min read
Subtitles make videos accessible and easier to find. What an SRT and a VTT file contain, how they differ, which rules make subtitles readable, and how to upload the file to YouTube.
Many people watch videos with the sound off: on the train, in an open-plan office, at night next to sleeping kids. For deaf and hard-of-hearing viewers, subtitles are the only way to follow what is said. And because search engines read text but not audio, subtitles also help your video get found.
What is inside a subtitle file?
A subtitle file is plain text: a list of cues, each with a start time, an end time and the text shown in between. The video itself stays unchanged; the player overlays the subtitles. That is why they can be switched on and off and corrected later.
SRT and VTT compared
| SRT (SubRip) | VTT (WebVTT) | |
|---|---|---|
| Time format | 00:01:02,500 (comma) | 00:01:02.500 (dot) |
| Header | none | starts with “WEBVTT” |
| Styling | barely | position, style, speaker tags possible |
| Typical use | YouTube, video editors, media players | HTML5 players, learning platforms, Vimeo |
In practice the difference is small. YouTube accepts both. If a program only knows one, it is usually SRT; web players prefer VTT because it is the W3C standard for subtitles in the browser.
Rules for readable subtitles
- At most two lines per cue; broadcasters typically use about 37 to 42 characters per line.
- Each cue should stay on screen long enough — as a rule of thumb at least one second, much longer for long sentences.
- Break lines at natural points: not between article and noun, not inside a name.
- With several speakers, show who is talking — with a name or a dash.
Automatically generated subtitles follow speech pauses, not these rules. On Sprechverlauf, each recognized passage becomes one cue; long sentences make long subtitles. For social media and learning videos, that is usually fine. For broadcast standards, shorten and break the lines in a subtitle editor such as Subtitle Edit or Aegisub.
Uploading subtitles to YouTube
- Open YouTube Studio and choose Subtitles on the left.
- Click the video and add a language if needed.
- Under Subtitles, click Add, then Upload file.
- Choose “With timing”, select the SRT or VTT file and publish.