A reader asked me today about chapter length. "My book is currently 45,675 words and I am starting on Chapter 30. Do you have an opinion on chapter length and word count?"
It can depend on the kind of book you're writing. Some formula fiction, especially romance, is sometimes written to fit into a precise number of printed pages. Production costs are low for such a standardized product, and no doubt even the chapters are a predictable length. It's cookie-cutter fiction.
But a novel can be any length, and so can a chapter. As I mentioned in my comments on Kurt Vonnegut a few days ago, he liked to write in very short chapters. Each chapter was practically a joke: Setup, minimal development, and punchline. It didn't seem very literary, but it sure made him readable.
My own chapters tend to run to maybe 5,000 words (20 double-spaced pages in manuscript). That's not because I want them to, but because that's how long it usually takes me to get from the opening situation through a number of difficulties for my characters, which culminate in a clearer understanding of the characters' situation.
That is, the reader should understand that the characters are in a hell of a fix, and maybe the characters themselves know it too. Either way, the reader should want to keep reading to see how they handle yet another fine kettle of fish I've gotten them into.
Every scene in the chapter should do something like this as well. Even if the story is deadly serious, it still follows the Vonnegutian joke pattern: We learn something unusual and intriguing, and then get an unexpected flash of understanding or recognition.
The technical term for this is anagnorisis: "ana" is Greek for "up," and "gnorisis" or "gnosis" means "knowledge." (This is where we get words like prognosis and agnostic.) In effect, when we get that flash of recognition we "uplearn"—we lose some of our illusions and rise to a better perception of the way the world really is.
On the level of the scene, we simply present some characters with a challenge and see how they handle it: Indiana Jones is resourceful robbing a tomb, but then panics at the thought of a snake. Each little flash gives us a clearer sense of where the story is taking us, and why we should care about the characters.
It may take four or five such scenes to build up to a major flash, or just one or two. If each scene ends in an "aha!", then each chapter should end with an "Omigod!"
The whole novel, of course, is building toward a climax in which the biggest flash of all will erupt and dazzle us: The butler did it! Oedipus killed his father and married his mother! Frodo's saved the world thanks to Gollum!
So if your story and your personal manner of telling it seem to require lots of short, punchy chapters, that's what you'll write. If you need a steady buildup of numerous scenes to get us to the "Omigod!" moment, then take your time.