Line length and number of lines
- Classic subtitles: up to about 42 characters per line and no more than two lines.
- Short-form social video: 1–5 words per caption feels faster and reads better on a phone.
- Break lines at natural pauses – not in the middle of a name or phrase.
Reading speed and timing
- Keep each caption on screen for at least about one second.
- Aim for no more than roughly 15–20 characters per second so viewers can keep up.
- Show captions in sync with the voice – word-level timing makes this automatic.
Try it for free
No sign-up, no watermark – your file is deleted automatically.
Fonts, size and contrast
- Use a clean, bold sans-serif. Avoid thin or decorative fonts for longer text.
- Make captions large enough to read on a phone at arm’s length.
- Add an outline, shadow or background box so text works on bright and dark scenes.
- Use color to emphasize a few key words – not whole sentences.
Placement and safe zones
- YouTube (16:9): bottom center, a little above the bottom edge.
- TikTok, Reels and Shorts (9:16): slightly below the middle – the bottom and right side are covered by buttons and text.
- Keep captions away from faces and from text that’s already in the video.
These rules are built into the HeyCaptions presets. Start with Classic for regular subtitles or Bold for social video captions and adjust from there.
Frequently asked questions
Should captions be uppercase?
Uppercase works for very short, punchy captions. For longer sentences, normal sentence case is easier to read.
Closed captions or burned-in captions?
Closed captions (a separate file) can be turned on and off and suit YouTube and websites. Burned-in captions always show and look the same everywhere – best for TikTok, Reels and Shorts.
Do captions need to describe sounds?
For deaf and hard-of-hearing viewers, good captions also describe important sounds, like [music] or [laughs]. You can add these in the Text tab.