How to add captions to a video (auto captions done right)
To add captions to a video, generate a transcript automatically, fix names and errors, split it into short timed lines, then either burn the captions into the picture (open captions, best for social video) or export an SRT file that viewers can turn on (closed captions, best for YouTube and accessibility). Many videos should have both. Here's how to choose, style and place captions so people actually read them. (Making a Short? See captions for vertical video.)
Open vs. closed captions
| Burned-in (open) | Closed (SRT/VTT file) | |
|---|---|---|
| Viewer can turn off | No | Yes |
| Works everywhere | Yes, part of the picture | Only where the platform supports caption files |
| Good for | Reels, TikTok, Shorts, silent autoplay | YouTube, websites, accessibility, translations |
| Search engines can read it | No | Yes, when uploaded as captions |
Step by step
- Transcribe automatically in your editor (or upload to YouTube for its auto captions).
- Fix errors: names, brands, jargon and numbers are where automatic transcripts miss most.
- Split into short lines: 32–42 characters per line for 16:9; 2–4 words at a time for vertical video.
- Time them so each caption appears with its words and stays long enough to read (roughly 1–6 seconds).
- Style and place them (below), then export: burn in, SRT, or both.
Make them readable
- High contrast: white text with a dark outline or background box.
- Big enough on a phone: for vertical video, captions should be readable at arm's length.
- Word highlighting (the current word in another color) helps viewers follow fast speech.
- Two lines maximum.
Put them where the platform won't cover them
| Where | Placement |
|---|---|
| YouTube (16:9) | Lower third, above the progress bar |
| Shorts, Reels, TikTok (9:16) | Middle third; the bottom and right edges are covered by buttons and captions |
Ask in words: "Keep the captions in the middle third, clear of the YouTube buttons", "Make the captions bigger and yellow on the current word."
Example
19 minutes of interviews became an 87-second YouTube video. Sped up. Phone-size version.
Novacut transcribed the speech on upload, timed every word, and burned in "karaoke" captions four words at a time, highlighting the current word. It also exports an .srt for YouTube, Premiere Pro or Resolve. Captions in Premiere →
FAQ
Why add captions if YouTube has automatic captions?
YouTube's captions are off by default and viewers must turn them on; burned-in captions show for everyone, including on silent autoplay. Uploading your own corrected SRT also fixes YouTube's mistakes.
What's an SRT file?
A plain-text caption file: numbered captions with start and end times. YouTube, Premiere, Resolve and most players accept it.
How accurate are automatic captions?
Usually very good on clear speech, weaker on names, jargon, accents and overlapping speakers. Always proofread before publishing.
Do captions help SEO?
Caption files uploaded to YouTube give it the full text of your video. Burned-in captions don't, so upload an SRT too.
Demo footage: NASA interviews with astronaut Jeanette Epps (public domain). NASA does not endorse Novacut. More on editing YouTube videos.