mimicHow it splits
Words are added to a line until the next word would pass your character limit (or word limit, if you set one). Lines are grouped into captions of 1 to 3 lines. With sentence breaks on, every sentence starts a new caption, so a caption never ends mid-thought into the next sentence.
Each caption lasts its word count × (60 ÷ your words per minute), never shorter than the minimum you set, plus a short pause after a full stop.
| Style | Max characters | Max words | Lines |
|---|---|---|---|
| Broadcast subtitles (Netflix) | 42 | – | 2 |
| Talking-head captions | Your call: shorter for vertical | – | 1 |
| Word-pop captions | – | 1 to 3 | 1 |
Netflix's English guide: 42 characters per line, two lines max, up to 20 characters per second for adults. Captions faster than 20 cps are highlighted.
Worked example
“I tried every serum on my shelf and this is the only one I actually finished.” at 32 characters per line, 160 wpm.
Caption 1: “I tried every serum on my shelf” (7 words × 0.375 s = 2.63 s).
Caption 2: “and this is the only one I” (7 words, 2.63 s). Caption 3: “actually finished.” (2 words; 0.75 s, raised to the 0.8 s minimum).
Sources
Questions
How many characters should a caption line be?
Netflix allows 42 characters per line, two lines max, for TV. Vertical video is narrower and captions are usually bigger, so creators tend to use far fewer; preview a line on your phone and pick what reads at a glance.
What speaking pace should I use?
Your own. Read part of your script aloud with the words per minute test, then enter the result here.
Are the timings exact?
No. They're estimated from your pace, which is fine for a script read-through or a first pass. To match the real audio, sync two lines in the timing shifter or time each word in an editor.
Is my script uploaded?
No. It's split and timed in your browser.