How to Make Subtitles Easy to Read: Length and Timing
Good subtitles disappear: viewers read them without noticing. A few simple rules make the difference between subtitles people can follow and ones that feel like homework.
Keep lines short
Aim for about 42 characters per line (about 20 for Japanese, Chinese and Korean) and at most two lines per subtitle.
Give people time to read
Show each subtitle for at least one second and no more than about six. A comfortable reading speed is around 17 characters per second.
Break lines at natural pauses
Split at punctuation or between phrases, not in the middle of a name. Two balanced lines look tidier than one long and one short.
Pick a clear style
Use a bold, plain font with white text on a dark outline or box, and keep subtitles away from the very bottom edge so apps do not cover them.
Why readability decides whether subtitles get read
Subtitles compete with the picture for attention. If a line is too long, flashes by too quickly or breaks in an awkward place, viewers stop reading and start guessing, or they simply look away. Readable subtitles feel invisible: people follow the story without noticing the text.
The good news is that readability follows a handful of simple rules, and you can apply them in the editor in a few minutes after the AI has written the draft.
Rules of thumb that work for most videos
- Two lines at most on screen at once, and shorter lines are better than long ones.
- Roughly 35 to 42 characters per line on a wide video; aim for less on a phone-sized vertical video.
- At least about one second on screen for even the shortest line, and enough time to read longer ones comfortably.
- Break at natural pauses, ideally at the end of a phrase or clause rather than between an article and its noun.
- Keep the text close to the speech. Subtitles should appear when the words are spoken and leave soon after.
These are guidelines, not laws. Fast comedy, slow documentary and a tutorial with demos can each justify slightly different choices.
Editing a line step by step
Play the video and read along. When a line feels crowded, split it: put the cursor at a natural pause and divide the text into two shorter cues. When a line flashes by, merge it with its neighbour or extend its end time so there is room to read.
It helps to read the text aloud at normal speaking pace. If you stumble, your viewers probably will too, and that is the place to rewrite or re-break the line.
Matching the style to the platform
Where the video will be seen changes what works. On a wide YouTube video, two short lines at the bottom are standard. On a vertical short video, a single line, kept short and placed above the interface at the bottom, reads best on a phone. For lectures and tutorials, slightly longer cues are fine because viewers are following along with their eyes on the screen.
If you are subtitling short clips, our guide on adding subtitles to TikTok, Reels and Shorts goes into placement and length. For a deeper look at the file itself, read what an SRT file is.
Quick tips
- Read your subtitles aloud; if you run out of breath, the line is too long.
- Check them on a phone, where text looks smaller.
- Keep the same style from the first subtitle to the last.
Ready to try it? Drop a video or audio file into the free subtitle generator and have subtitles in minutes. Open the generator →