Free Readability Checker for Clear, Human-Sounding Text

Paste your text or upload a file and get a readability score: reading ease, grade level, difficult words, and sentence complexity. This free readability checker shows you exactly where your writing loses readers.

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FAQ

What is a readability checker?: A readability checker is a tool that analyzes text and returns a score showing how easy it is to read. It uses established formulas (Flesch-Kincaid, Gunning Fog, SMOG, and others) to calculate a grade level and reading ease score based on sentence length, word length, and syllable count. GPTinf's readability checker highlights the specific sentences and words that are dragging your score down.
Is GPTinf's readability checker free?: Yes. The readability checker is free to use with no account required. Texts between 30 and 500 words can be checked without signing in. Creating a free account raises the limit to 5,000 words per check. There is no daily limit on the number of checks at either tier.
Is there a word limit for the readability checker?: Without an account, the checker analyzes up to 500 words per submission. A minimum of 30 words is required for the formulas to return reliable results. If you paste more than 500 words without signing in, the tool analyzes the first 500 words and displays results for that portion. Creating a free account raises the per-check limit to 5,000 words. File uploads (.txt, .doc, .docx, .pdf) follow the same word limits based on account status.
What does grade level mean in a reading level checker?: Grade level indicates the U.S. school grade at which a typical student could read the text without difficulty. Grade 6 means a 6th grader (approximately 11–12 years old) can read it comfortably. Grade 12 requires a high school senior's reading proficiency. Grade levels above 12 correspond to college and graduate-level text.
What does a Flesch-Kincaid score mean?: The Flesch-Kincaid Reading Ease score runs from 0 to 100. A score of 60–70 is plain English, comfortable for most adult readers. Below 30 is very difficult, typical of academic or legal text. The Grade Level version of the same formula translates your text into a U.S. school grade: a score of 8 means an 8th grader can read it without difficulty. GPTinf displays both alongside five other formula scores so you can compare across standards.
Why does AI-generated text score poorly on readability checkers?: AI language models are trained on corpora that include large amounts of academic, formal, and technical writing. This training data shapes the model's default register toward formal vocabulary, long compound sentences, and passive constructions, all of which raise grade level and lower reading ease scores. Unedited AI output commonly returns Flesch-Kincaid grade levels of 13–17 for content intended for a grade 8 audience.
Can I check the readability of an email?: Yes. Paste your email subject line and body copy into GPTinf's readability checker to see the grade level and reading ease score before you send. For most marketing emails, a Flesch-Kincaid Reading Ease of 70 or above and a grade level of 6 or below keeps copy accessible to readers scanning fast on mobile.
Does readability affect Google rankings?: Readability is not a disclosed direct ranking signal in Google's search algorithm. However, content quality signals that correlate with readability (time on page, bounce rate, engagement) are factors that influence ranking. Pages with lower readability scores tend to show higher abandonment rates on informational queries where the reader expected plain-language content.
What readability level should my content be?: It depends on your audience and content type. For blog posts and general web content, grade 7–9 hits the widest audience. For emails and social content, grade 5–6 is more effective. Academic writing typically sits between grade 10 and 14. The key is matching the grade level to the reader, not defaulting to whatever the AI or your first draft produces. GPTinf's checker shows you where you are so you can decide whether it's where you need to be.
What's the difference between difficult words and complex words?: Difficult words are words that fall outside a standard list of common everyday vocabulary — words a general reader is likely to stumble over or look up. Complex words are defined specifically as words with three or more syllables, which is the measure used by Gunning Fog and SMOG. Both types raise your grade level and lower your reading ease score. GPTinf flags both categories in your text so you can see them at a glance and choose which to replace.

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