Caption reading speed
Can people actually read your captions?
Captions that change faster than people can read them are as good as none. Drop in your captions file and see which lines go by too fast, exactly when they appear, and how to fix each one. Nothing is uploaded.
Characters (letters, spaces and punctuation) per second; in a .vtt file, styling and speaker tags aren’t counted. YouTube has no rule; 17 a second is the usual subtitling standard, and slower is kinder for children and for people reading in a second language.
How fast is too fast?
Reading speed is measured in characters per second: letters, spaces and punctuation, divided by how long the caption is on screen. YouTube doesn’t set a limit, so this uses the norms professional subtitlers work to. About 17 a second suits most adults; children, and anyone reading in a language that isn’t their first, need it slower.
Fixing a fast caption
There are two ways: leave it on screen longer (start it a little earlier, or end it a little later if nothing follows straight away), or say the same thing in fewer words. Where speech is fast, captions can paraphrase a little: “We’re going to go ahead and start” reads just as well as “Let’s start”.
YouTube’s automatic captions
Automatic captions follow the speech, not a reading speed, so where you talk fast they can go by too fast to read. Download them and check them here; fix any that are, and publish your edited version.
Related: more tools for YouTube creators · the broadcast version, with every subtitle format and delivery spec.