As long as it needs to be. No authority states a chapter length, and the range everyone quotes traces back to blogs, by the admission of the Chicago Manual of Style's own editors.
That is not a dodge. It is the actual state of the evidence, and knowing it frees you from a number that was never real.
What Chicago Actually Says
The Manual's only relevant statement, quoted on its own blog, concerns non-fiction and does not answer the question:
"CMOS 1.49 (17th ed.) concerns itself only with nonfiction, stating that books 'are divided into numbered chapters of a more or less consistent length.' That applies to fiction, too, but it doesn't answer the question of how long."
The blog post then gives the familiar figures, "Short is generally pegged at 1,500 words; long is over 5,000", and attributes them plainly:
"Plenty of bloggers have examined chapter lengths for various fiction genres in order to come up with typical word counts."
So the most-cited range in this topic is, by the Chicago Manual of Style's own account, blogger-derived. It links out to those blogs without endorsing any figure.
The same post also asserts that "Epic fantasy usually weighs in with by far the longest chapters. Romance, literary fiction, and young adult novels clump together with mid-length word counts", again without a cited source.
No corpus study of chapter length appears to exist, and no publisher submission guideline states one.
What Chicago Recommends Instead
Their conclusion is worth taking seriously precisely because they decline to give a number:
Figuring out when and how to close a chapter is best done by intuition. And the best way to develop intuition is by reading books.
The one thing the Manual does say is about consistency: chapters of "a more or less consistent length". That is a more useful constraint than any absolute figure, because a reader notices variation more than duration.
The Useful Framing
Since length is unspecified, the real questions are about function.
A chapter is a unit of attention. It is where a reader can stop. Chapter length is really a decision about how often you offer them that exit, and how badly you want them not to take it.
Short chapters accelerate. Frequent breaks create momentum and are conventional in thrillers. They also make a book feel faster than its word count.
Long chapters immerse. Fewer exits mean deeper submersion, at the cost of making the book feel heavier.
Consistency matters more than length. A book of 2,000-word chapters with one of 9,000 makes that chapter feel like a fault, whatever its quality.
End on a reason to continue. The break is the decision point, and what precedes it is doing the persuading.
Chicago also notes what a chapter is, structurally, which is less than people assume: "a chunk of a book that comes to a recognizable end, usually marked by a page break or by an extra space followed by a new numbered or titled chapter." A typographic division, not a narrative unit with rules.
Do Not Confuse This With Word Count
Whole-novel length is defined authoritatively, unlike chapter length. The SFWA's Nebula Award rules, effective 1 January 2025, define a novel as "40,000 words or more", a novella as "at least 17,500 words but fewer than 40,000 words", a novelette as "at least 7,500 words but fewer than 17,500 words", and a short story as "fewer than 7,500 words".
Those are award category boundaries rather than writing advice, and they say nothing about chapters. But they are the one hard definition in this territory.
What Deckle Does
Word counts are per document, so each chapter and scene carries its own, visible in the Binder and the Outliner. That gives you the one thing the sources say actually matters: whether your chapters are of "more or less consistent length". Scanning the column is faster than any rule, and it shows the outlier immediately.
The Outliner shows every chapter's length alongside its synopsis, which is where an overlong chapter usually reveals itself as two chapters.
Splitting is cheap. Because chapters and scenes are separate documents, breaking one in half or merging two is a structural operation rather than a cut-and-paste through a long file.
There is no chapter length target or warning in Deckle, and given that no authority publishes one, adding a threshold would be inventing a rule rather than enforcing one.
For chapter count, see how many chapters should a novel have, and for the units inside them, scene vs chapter.
Common Mistakes
- Treating 1,500 to 5,000 words as a rule. Chicago's own blog attributes it to bloggers.
- Making chapters uniform to hit a number. Consistency is about not jarring the reader, not about arithmetic.
- Splitting a chapter only because it is long. Split it where it has two centres of gravity.
- Assuming genre dictates length. The claim that it does is asserted without a source.
- Ending chapters at natural resting points throughout. Some should end where a reader cannot comfortably stop.
- Confusing chapter length with novel length. Only the second has authoritative definitions.
FAQ
Q: How many words should a chapter be? A: No authority states a figure. The circulating 1,500 to 5,000 range is attributed by Chicago's editors to bloggers.
Q: Should all my chapters be the same length? A: Roughly. The Manual's only guidance is "a more or less consistent length".
Q: Are short chapters better? A: They read faster and suit thrillers. Neither is better; they do different things.
Q: Is there research on this? A: None found. No corpus study of chapter length appears to exist.
Q: What about total novel length? A: That is defined. SFWA sets a novel at 40,000 words or more for award purposes.