What each metric means

This is the reference. Every metric the engine reports, defined in plain English. For how the engine computes them and why there is no AI involved, see How the engine works.

Readability

Reading Ease

Flesch-Kincaid Reading Ease, on a 0 to 100 scale. Higher scores mean more accessible prose. The formula weighs average words per sentence and average syllables per word. Most adult fiction targets 60 to 80. Simpler prose scores higher; dense, complex sentences score lower.

FK Grade

Flesch-Kincaid Grade Level, an estimate of the US school grade level needed to read the text comfortably. It is calculated from words per sentence and syllables per word. For most fiction, grades 6 to 9 is the target range. It reflects sentence and vocabulary complexity, not sophistication.

Vocabulary Complexity

A measure of how often your text uses less common words. Higher values mean vocabulary that is less familiar to a general reader. This is neither good nor bad on its own. It depends on what you are writing and who you are writing for.

Reading Level (Coleman-Liau)

An alternative grade-level estimate based on characters per word and sentences per 100 words rather than syllables. It often disagrees with FK Grade slightly. When the two diverge by more than two grade levels, Inkbreaker notes it and explains the discrepancy.

Reading Time

An estimate of how long the passage takes to read at average adult silent reading speed, based on Brysbaert's 2019 research. The formula is word count divided by 238 words per minute.

Structure

Average Sentence Length

Total words divided by total sentences. Genre benchmarks reflect expected prose rhythm. Very short averages can feel choppy. Very long averages can feel dense and hard to follow.

Sentence Length Variation

The standard deviation of sentence lengths across the passage. High variation produces more natural, engaging rhythm. When sentences are all roughly the same length, prose starts to feel mechanical.

Word Count

The total number of words. For exercises with a set word count target, this is scored against that target. Otherwise it is scored against a general benchmark for the writing type.

Sentence Count

The total number of sentences. Informational.

Paragraph Count

The total number of paragraphs. Measured against benchmarks for pacing and density appropriate to the writing type.

Vocabulary

Vocabulary Range

The ratio of unique words to total words (type-token ratio). Higher values mean more varied vocabulary. Very low scores can signal repetitive or limited diction.

Lexical Density

The proportion of content-carrying words (nouns, verbs, adjectives, adverbs) to total words. Higher density means more information per sentence. Very low density often means filler.

Repetition Score

A measure of overused non-stop words. Low scores mean more varied word choice. High scores flag repeated content words that may be wearing out their welcome.

Style

Passive Voice

The percentage of sentences in passive construction. Active voice tends to feel more immediate. Benchmarks vary by writing type: screenwriting allows higher passive voice (up to 40 percent) because action lines are conventionally passive, while fiction targets 30 percent or lower.

Adverb Density

The percentage of words ending in -ly. High adverb density is often a proxy for telling rather than showing: naming an emotion or quality with an adverb instead of dramatizing it.

Dialogue Ratio

The proportion of the text in quoted dialogue. Tracked for fiction. Suppressed for short passages under roughly 300 words, where the ratio is not statistically meaningful.

Syntactic Depth

The proportion of sentences using subordinate clauses, embedded clauses that layer detail into a sentence rather than stating things flatly. Higher syntactic depth often correlates with showing rather than telling. Flat syntax can signal summary or narration at the expense of scene.

Sentence Opening Variety

How often sentences begin with different words or constructions. When many sentences start with the same word or pattern, the rhythm gets repetitive.