Guide
Subtitle timing and reading speed
When a subtitle feels wrong, the problem is usually timing rather than translation. The viewer has to read the line, watch the picture, and listen, all at once, and reading is the part that loses when there is not enough time.
Characters per second is the real unit
Subtitling is not measured in words. It is measured in characters per second: how much text is on screen divided by how long it stays there. A line is comfortable when a viewer can read it, glance at the picture, and still be finished before it disappears.
The commonly used ceilings in professional subtitling sit around seventeen characters per second for adult audiences, dropping to roughly thirteen for content aimed at children, who read more slowly. These are conventions rather than laws, and different broadcasters publish slightly different numbers, but they cluster tightly enough to treat as a working range.
Minimum and maximum durations
| Minimum on screen | Around five sixths of a second. Anything shorter registers as a flash rather than as text, even if it is only two words. |
|---|---|
| Maximum on screen | Around six to seven seconds. Past that, viewers start re-reading a line they have already finished, which is oddly uncomfortable. |
| Gap between subtitles | A small gap, traditionally two frames. Without it, consecutive subtitles look like one continuously mutating block. |
| Lines per subtitle | Two at most. A third line covers too much picture and pushes past what can be read in the time available. |
Why translated subtitles break timing
The timings come from the original speech. The text does not. When a translation runs longer than the original, the same window has to hold more characters, and the characters-per-second figure climbs past what is readable without anyone changing a timing value.
- Most European languages run longer than English. Spanish, French, Portuguese, Italian, German, Polish, and Russian all tend to need more room for the same sentence.
- East Asian languages usually run shorter in character count. Chinese and Japanese pack more meaning per character, which gives the timing back.
- Agglutinative languages such as Finnish, Hungarian, and Turkish produce long unbreakable words, which constrains where a line can split even when the total length is fine.
- The fix is condensing rather than reflowing. A good subtitle translation says the same thing in fewer characters, which is a different skill from translating a document.
Where to break a line
Given a line that has to become two, the break should fall where the sentence naturally pauses. Breaking after a comma, before a conjunction, or between clauses keeps the phrase intact. Breaking between an article and its noun, or splitting a name across two lines, forces the reader to reassemble the sentence, which costs time you do not have.
Diagnosing a subtitle that feels wrong
- It feels rushed: too many characters for the duration. Condense the text rather than extending the timing into the next line.
- It lingers: the subtitle outstays the speech. Trim the end time rather than padding the text.
- It flickers: consecutive subtitles with no gap between them. Add the gap.
- It arrives late: an offset problem, and usually constant across the whole file, which makes it easy to correct in one move.
- It drifts progressively: a frame rate mismatch rather than a timing error, and it needs the source fixed rather than the subtitles nudged.
Generate subtitles fitted to your own footage with 50 free credits.
Continue with Google50 free credits. No credit card needed.Frequently asked questions
How many characters should a subtitle line be?
Professional practice clusters around the high thirties to low forties per line, with two lines maximum. The real constraint is reading speed rather than the count itself.
How long should a subtitle stay on screen?
Long enough to read comfortably, which usually means at least five sixths of a second even for very short lines, and no more than about six or seven seconds for long ones.
Why do translated subtitles feel faster than the original?
The timings came from the original speech, and most translations run longer than the English they replaced. The same window now holds more characters, which raises reading speed past comfortable.
Can I fix subtitle timing after the subtitles are generated?
Yes, on the Pro and Studio plans. The subtitle editor lets you adjust wording and timings, then reburn the video.