Readability Score Checker
Analyze your writing with five commonly used readability formulas. Compare passages and find sentences that may need a closer edit.
Analyze a passage
Analyze your text with Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog, Coleman-Liau, and SMOG indices.
Why Readability Matters for Authors
Readability formulas estimate surface complexity from features such as sentence length, word length and syllable count. They can help you spot a chapter or paragraph that reads very differently from the rest of a manuscript.
A score cannot tell whether a scene is compelling, a fact is correct or a technical term is necessary. Use it to choose passages for review, then make the editorial decision by reading those passages in context.
This browser-based checker estimates English syllables with a vowel-pattern heuristic and identifies sentence endings from punctuation. Names, abbreviations, dialogue and unconventional formatting can affect the result, so treat every score as an approximation rather than a certification.
The 5 readability formulas explained
- Flesch Reading Ease: Combines average sentence length and average syllables per word. Higher scores indicate lower measured complexity.
- Flesch-Kincaid Grade: Uses sentence length and syllables per word to return a grade-like number. It does not guarantee comprehension at that grade.
- Gunning Fog Index: Uses average sentence length and the share of words with three or more syllables.
- Coleman-Liau Index: Uses average letters and sentences per 100 words instead of estimating syllables.
- SMOG Index: Uses polysyllabic word count and sentence count. This checker returns it only when it detects at least three sentences.
Choose a useful comparison baseline
Start with the reader
Decide what the reader already knows, which terms the subject requires and how quickly the passage needs to move. Those choices matter more than a universal genre target.
Compare like with like
Analyze several passages from the same manuscript. A section that sits far outside the project's normal range is a better editing signal than comparison with an unrelated genre.
7 Ways to Improve Your Readability Score
Shorten overloaded sentences
When one sentence carries several clauses or ideas, split it at a natural boundary and check that the meaning still holds.
Prefer the clearest accurate word
When two words carry the same meaning for this reader, the more familiar one may reduce friction. Keep a technical or precise term when the simpler substitute changes the meaning.
Check what each modifier adds
A more precise verb can sometimes replace an adverb, but not every modifier is expendable. Remove it only when the sentence keeps the intended emphasis, rhythm, and meaning.
Break up dense paragraphs
Start a new paragraph when the subject, speaker or step changes. The break should follow the structure of the passage.
Compare active and passive voice
Active voice is often shorter when the actor matters. Passive voice can be clearer when the actor is unknown, obvious, or less important than the action, so choose by context.
Read it aloud
A stumble can reveal crowded syntax or an awkward transition that silent reading missed. It is a review signal, not proof that every reader will struggle in the same place.
Test one main move per sentence
When a sentence makes several separate moves, try splitting it and compare both versions. Keep the longer structure when the ideas genuinely belong together and remain easy to follow.
Use the Score as a Diagnostic, Not a Writing Target
A readability formula measures sentence length and word complexity; it cannot judge suspense, accuracy, voice, emotional impact, or whether a technical term is necessary. Test a representative chapter instead of rewriting every sentence to chase one number. When a section scores much harder than the rest, inspect it for long sentences, unexplained terminology, or dense paragraphs. Then read the revision aloud and confirm that the meaning and author voice still sound natural. The strongest edit improves comprehension without making every sentence identical.
Frequently Asked Questions
What is a good Flesch Reading Ease score?
There is no universal target. Compare passages written for the same audience and use a large change in score to find sections that may need a closer edit. The formula estimates surface complexity; it does not measure accuracy, voice, or reader interest.
What readability level should I target for my book?
Start with your intended reader and the language the subject requires. Analyze several representative chapters, compare their ranges, and inspect passages that differ sharply from the rest. Do not rewrite necessary terms or character voice just to reach one number.
How do I improve my readability score?
Inspect unusually long sentences, dense paragraphs, complex words that have a clearer alternative, and modifiers that add little meaning. Active voice may be shorter in some passages, while passive voice can be appropriate when the actor is unknown or less important. Recheck the score, then keep only edits that improve the passage for its intended reader.