The short version
- Keep each caption to one or two short lines — roughly 32–42 characters per line.
- Leave each caption on screen long enough to read: at least about one second, and longer for longer lines.
- Break lines at natural pauses, not in the middle of a phrase.
- Use a bold font with an outline or background box so text stays readable over any footage.
- Place captions in the lower-middle of the frame, clear of app buttons.
Captions, subtitles and burned-in text
The words are often used interchangeably, but there are real differences worth knowing:
| Type | What it is | Best for |
|---|---|---|
| Open (burned-in) captions | Text drawn into the video pictures. Always visible, looks the same everywhere. | Social feeds, where autoplay is silent and you want full control over style. |
| Closed captions | A separate text file (such as SRT or VTT) uploaded alongside the video. Viewers can turn them on or off. | YouTube, websites and courses, where viewers expect to control them. |
| Subtitles | A translation of the dialogue into another language. | Reaching viewers who speak a different language. |
| Captions for accessibility (SDH) | Dialogue plus important sounds — [music], [door slams], [laughter] — and who is speaking. | Making content fully accessible to deaf and hard-of-hearing viewers. |
For TikTok, Reels and Shorts, burned-in captions are the norm: they autoplay muted and you choose exactly how the text looks. For titles, labels and lower thirds, see our guide to adding text. Many platforms also offer automatic captions — they're a helpful extra, but check them, because speech recognition makes mistakes with names, accents and jargon.
Rules for readable captions
Professional subtitling guidelines vary a little between broadcasters and streaming services, but they agree on the essentials:
Keep lines short
A common limit is around 32 to 42 characters per line and no more than two lines at once. On vertical video, where the frame is narrow, shorter is better — three to six words per caption works well and matches the fast pace of short-form content.
Give people time to read
Most viewers read somewhere around 15–20 characters per second comfortably. As a practical rule: show short captions for at least about one second, and longer captions for proportionally longer. If you find yourself cramming text, split it into two captions or trim the wording.
Break lines in sensible places
Split lines where you'd naturally pause, so each line is a complete chunk of meaning:
- ✔ "This is the easiest way / to fix shaky footage"
- ✘ "This is the easiest way to / fix shaky footage"
Avoid splitting an article from its noun ("the / camera"), a name, or a verb from its helper ("can / help").
Edit lightly for clarity
You don't have to transcribe every "um" and repeated word. Tidy obvious filler, but don't change the meaning — viewers who can hear the audio notice when captions say something different.
Styling captions
- Contrast first. White text with a dark outline, or text on a solid box, stays readable over bright skies and busy scenes alike.
- Choose a clean, heavy font. Script and decorative fonts look nice for titles but slow down reading for captions.
- Size for phones. Captions that look big on a computer are often too small on a phone. Preview at phone size.
- Be consistent. Same font, size, style and position throughout, so the eye always knows where to look.
- Highlight sparingly. A different colour for a single key word can add energy; colouring everything removes the effect.
Where to put them
The traditional spot is the bottom centre. On vertical social video, the very bottom is covered by the app's caption and username, so place captions a little higher — roughly the lower third, just below the middle. Keep them clear of the right edge where the like and share buttons sit. Our vertical video guide explains these safe zones in detail.
If something important appears at the bottom of the frame — a product, a scoreboard, on-screen text in the footage — move the captions up for that moment rather than covering it.
Step by step: add captions in VDOAPP
VDOAPP creates burned-in captions — perfect for social platforms. Everything happens in your browser with the free online editor.
- Finish your edit first. Captions are timed to the picture, so lock the cut before you start.
- Write a transcript. Play the video and type out what's said, split into short phrases. A notes app is fine.
- Add the first caption. Move the playhead to where the first phrase starts, open the Text tab and press + Add text. New text starts at the playhead.
- Style it. Choose Inter or Bebas Neue, the Outline or Box style, a size that's readable on a phone, and drag it into the lower-middle of the frame.
- Time it. Set Show from and Until so the caption appears as the words are spoken and disappears as the phrase ends. Use the arrow keys to step frame by frame for precision.
- Repeat for each phrase. Captions appear as bars on the text row of the timeline, so you can see gaps and overlaps at a glance.
- Add subtle motion (optional). A quick Pop or Fade in animation helps captions feel lively. Keep animations short so they don't delay reading.
- Watch it muted. Play the whole video with sound off. If you can follow it comfortably, your captions work.
Captions are one part of accessibility — see our video accessibility guide for the rest.
Caption checklist
- No more than two lines on screen at once
- Lines broken at natural pauses
- Each caption visible long enough to read comfortably
- High contrast and readable at phone size
- Clear of the app's buttons and the bottom caption area
- Names, brands and technical terms spelled correctly
- Matches what's actually said