Fix subtitle lines that run too long.

A caption is read in a glance, so the eye needs the break to fall where the sentence would pause anyway. Break after a full stop and the reader finishes a thought. Break after a comma and they finish a clause. Break between an adjective and its noun and they have to hold the first line in their head while they read the second.

That is why a naive wrap at the character count reads worse than a slightly uneven one. This tool ranks the possible break points: a sentence end first, then a clause end, then a position just before a word that opens a phrase, such as and, but, that, or to. Only when none of those fit does it fall back to the most balanced split. It never breaks inside a word.

For the editorial side of the same question, which lines to keep together and how captions should track speech in a vertical clip, read the caption line break guide.

Some cues carry more text than two lines can hold at any sensible limit. The common answer is to split the cue into two and divide the duration between them by character count. This tool does not do that, and the reason is worth stating plainly.

Splitting a cue invents a new cue boundary and rewrites timing. If someone has already checked that file against the video, that check is quietly invalidated, and nothing on screen tells you it happened. So those cues are reported instead, with the length of their longest line, and left exactly as they were.

The right fix is usually to shorten the wording, which you can do where the caption text is still editable in the AutoCaption caption generator. If a cue genuinely needs splitting, do it somewhere you can watch the result against the video.

The limit is measured in grapheme clusters, the units a reader perceives, not in code units. It makes no difference to English, where the two counts are identical, and a large difference to Indic scripts, where a syllable is several code units and one visual unit. A breaker counting code units splits Devanagari and Kannada lines that never needed splitting.

What it does not do is measure width or height, which is what the limit is really about. The guide to subtitle character limits covers both halves, including why Nastaliq and vertically stacked scripts still need checking in the player.

Rewrap late. A translation changes the length of every line, so breaks set before translating do not survive it; the translation guide covers what else moves. Retiming does not change text length, so it can happen either side, using the subtitle timing shifter.

Check afterwards rather than assuming. Run the rewrapped file through the subtitle validator, which reports line length alongside reading speed and timing faults, and read the reading speed guide for what the numbers mean. Rewrapping fixes line length; it does not make a fast cue slower.