There are no hard-and-fast rules, but it pays to listen to those who have spent years in the industry. To arrive at the definitions below, I conflated opinions from two sources: Standout Books and an article by Chuck Sambuchino. Links are at the end.
110,000 words + epic/saga
70,000 – 110,000 novel
50,000 – 70,000 short novel
10,000 – 50,000 novella
500/1000 – 10,000 short story
500 or under flash fiction
The novella is enjoying a resurgence, particularly as it is a popular length on Kindle. Anyone who has written a work of 90,000 words might consider publishing it as two or three novellas instead of one novel. Readers like series: it’s good if you can get them hooked after the first one. However, I would seek expert advice before taking that decision.
The riskiest of the six categories above is undoubtedly the epic or saga. If you are unknown, a work of this length is usually too risky for a traditional publisher. Most publishers I have talked to advise staying well under 100,000 words.
Some articles recommend dividing a 50,000-word story into ten chapters of 5000 words. This solution sounds neat but defies logic. The length of a chapter should be determined by content. The end of an action sequence, an important scene, or a phase in the narrative should dictate where a chapter ends, not word count.
Notwithstanding the above, the trend is towards shorter chapters. A novel of 300 pages is more likely to have 30 chapters of 10 pages than 10 chapters of 30 pages. Long chapters can become tiresome, and readers like to end a reading session at the end of a chapter.
You would expect paragraph length to vary as much as chapter length, but normally it doesn’t. The 16 novels I examined before writing this were remarkably consistent. On an average page containing 250 – 300 words, with no dialogue, you can expect to find three paragraphs. With dialogue, it’s more difficult to count paragraphs.
The overriding consideration is the digestibility of each chunk of text and how it appears on the page. Readers don’t like solid, page-long blocks of text with no breaks or indentations.
The length of sentences is far more important than the length of chapters. Advice on the average length to aim for is extraordinarily divergent: I’ve seen recommendations as high as 20 – 25 words and as low as 12 – 15. The key points are:
(1) Vary sentence length.
(2) Don’t use too many long sentences.
(3) Throw in a few sentence fragments*.
*A sentence fragment is a short utterance without a main verb, e.g. No luck; Not a chance; Silence. It’s useful to insert one or two of these after a particularly long sentence. It gives your reader a breather.
It’s worth expanding the warning about long sentences. As a student, I had to read “A Study of Goethe” by Barker Fairley. I hated it. By the time I got to the end of a sentence, I couldn’t remember the beginning. I have searched the internet in vain for an extract from Fairley’s book, but I found a review of it. The language of the reviewer is no better:
“He sees him moving with painful slowness from a state of utterly chaotic unbalance to a more harmonious co-ordination of his varied, but often conflicting, powers and to the responsible adjustment of his own individuality to the community.”
Got it? That sentence has 38 words. You need to concentrate too hard to get the sense. It’s far better to break it into two or three sentences.
The gov.uk blog has announced that the maximum word count for sentences in their articles is now 25 words. They cite writing guru Ann Wylie, who quotes research findings as follows:
Average sentence length 14 words – readers understand 90%.
Average sentence length 43 words – readers understand less than 10%.
J.K. Rowling’s average in the Harry Potter books is 12 words.
How sophisticated a writer’s language is depends on the target audience, but the trend is towards shorter, simpler words. Hemingway was once challenged on why he didn’t use more erudite vocabulary. His reply was that he knew higher-level words but did not wish to limit his audience.
Hemingway deserves praise for this generous consideration of his readers. At the same time, some of his disciples have extended his ideas beyond what he would have wished. If the watchword is “Simply, simplify, simplify” you end up with dumbing down and an unfortunate end result: “Simplify yourself stupid.” If I feel that strutted, sauntered, or ambled add more to a scene than walked, then I will not write walked.
When reading a book, I don’t want to fly to the dictionary every five minutes, but I’m grateful if a writer can teach me a handful of new words.
In a word: think short. Reading habits have changed, and we have to adapt our writing to fit in with readers’ lifestyles. We live in a world of sound bytes, abbreviations, and shrinking attention spans. Consider commuters reading novels on crowded trains. They’re stressed. They don’t want the extra stress of complex sentences or pages with no paragraphs. We need to make our writing punchy and varied. If we make their lives easier, we’ll make their reading more enjoyable.
Sources for word count of books: