Score text as you edit
Paste an English draft and six readability scores compute on every keystroke, along with a consensus grade averaged across the grade-level formulas. Shorten a sentence and watch the grade change to see which passages add the most mechanical difficulty.
The Hardest sentences panel ranks your three most difficult sentences by their individual Flesch-Kincaid grade. This is usually more actionable than the overall score, because readability problems concentrate: two or three long sentences drag an otherwise plain paragraph.
The six formulas
- Flesch Reading Ease (0 to 100, higher is easier) weighs sentence length and syllables per word. Above 60 counts as plain English; most insurance policies score below 30.
- Flesch-Kincaid Grade converts the same inputs into a US school grade. A score of 8.2 means an average 8th grader can follow it.
- Gunning Fog counts “complex” words of three or more syllables. It reacts strongly to jargon-heavy prose even when sentences are short.
- SMOG estimates the grade needed for full comprehension from polysyllable density. It was built for health-care materials and runs about a grade higher than Flesch-Kincaid.
- Coleman-Liau uses characters instead of syllables, so it penalizes long words like “notwithstanding” regardless of how they break into syllables.
- Automated Readability Index (ARI) also works from characters and sentence length; it was developed for military technical manuals.
Example: same message, two grades
The built-in example makes the mechanics visible. “The implementation of the proposed organizational restructuring necessitates comprehensive stakeholder consultation” scores at post-graduate level: 9 words, 5 of them complex. “We looked at the plan” scores around grade 1. Both paragraphs of the example say roughly the same thing, several grades apart.
What the scores cannot see
Every formula here reduces to word length and sentence length. None of them notice passive voice, ambiguous pronouns, buried verbs, or logical gaps, so a grammatically scrambled text with short words still scores as “easy”. A low grade confirms that the text is not mechanically dense; it does not confirm that the writing is clear or correct.
The formulas and syllable rules are calibrated for English. Clearly non-English text produces an error instead of a grade. Short or mixed-language samples can be ambiguous, so check that the input is English before relying on the result.
Word and time counts
The stats row includes total words, sentences, syllables, average sentence length, complex-word count, and an estimated silent reading time at 238 words per minute, the average adult rate for non-fiction. For a plain word count with keyword density, the word counter tool goes deeper.