Sentence rhythm, measured
Readability numbers for fiction, not for business memos
Average sentence length, how much that length varies, adverb density, estimated passive voice, dialogue share and reading grade. The variation number is the one most writers have never seen and most need.
- Six measures
- Not one opaque score you cannot interrogate.
- Per chapter
- Compare the weak chapter against the strong one.
- Stable
- Same text, same numbers, every run.
A single readability score tells you almost nothing about a novel. What is useful is the spread: competent prose that still feels flat is usually prose where every sentence is the same length, and that is a number you can actually see.
Sentence length and its variation
The standard deviation matters more than the average. Low variation is what makes technically clean writing feel monotonous.
Adverb density
Adverbs per thousand words, so a chapter is compared against the rest of your book rather than against a rule someone invented.
Estimated passive voice
A share, not a verdict. Passive is right sometimes, and the number exists to be judged rather than minimised.
Dialogue share
How much of the chapter sits inside quotation marks. Useful when a book starts feeling like people talking in a white room.
How it goes
- 1
Import the manuscript
Every chapter gets its own set of numbers.
- 2
Compare chapters
The outliers are where to look first.
- 3
Decide what to change
The tool has no opinion about the right value, and says so.
Questions
What is a good reading grade for a novel?
There is no correct answer, which is why no target is shown. Commercial fiction often lands between grade 6 and 9, literary fiction sits higher on purpose, and neither is wrong.
Is passive voice bad?
No. It is the right choice whenever the object matters more than the actor. The number exists so you notice when it has crept in everywhere, not so you drive it to zero.
How is this different from my word processor?
Those give one score for a whole document. This breaks it down per chapter and adds the variation measure, which is the one that actually explains flat prose.