Free Readability Checker - Flesch Score and Grade Level
Paste any content and get an instant readability score using the Flesch Reading Ease formula. See your grade level, average sentence length, passive voice usage, transition word frequency and more - with specific suggestions to improve. Select your target audience for tailored scoring. No signup required.
What Does This Readability Checker Measure?
Flesch Reading Ease
The industry standard readability score from 0 to 100. Calculated using average sentence length and syllables per word. Higher scores mean easier reading.
Grade Level
Flesch-Kincaid Grade Level translates your readability score into a US school grade equivalent. Grade 8 means readable by a typical 13 to 14 year old.
Sentence Length
Average words per sentence and a list of your longest sentences flagged for review. Long sentences are one of the biggest readability killers.
Complex Words
Percentage of words with three or more syllables. High complex word counts make content harder to read regardless of sentence length.
Passive Voice
Percentage of sentences using passive voice. Active voice is more direct, easier to read, and more engaging for most audiences.
Transition Words
Percentage of sentences using transition words like however, therefore, and additionally. Transitions help readers follow your logic and improve perceived quality.
Adverb Density
Number of -ly adverbs per 100 words. Overuse of adverbs often signals weak verb choices. "She spoke quietly" is weaker than "she whispered".
Target Audience Scoring
Switch between General Public, Professional and Academic to get scoring thresholds appropriate for your actual audience rather than a one-size-fits-all benchmark.
How to Use the Readability Checker
Select Your Audience
Choose General Public, Professional or Academic depending on who you are writing for. This adjusts what scores are considered good or bad.
Paste Your Content
Paste your article, blog post, email or any text into the input area. The tool analyses it live as you type so you see results immediately.
Review Your Scores
Check the Flesch score, grade level and the eight metric cards. Green means good, amber means borderline, red means worth fixing.
Act on Suggestions
Work through the suggestions panel and the flagged long sentences. Edit your content, paste it back in, and watch your score improve in real time.
Readability and SEO
Google does not use readability as a direct ranking factor. However readability has a significant indirect impact on SEO. Content that is easy to read tends to have lower bounce rates, higher time on page, and more return visits - all of which send positive engagement signals to Google.
Readable content is also more likely to earn backlinks and social shares because people recommend content they found genuinely useful and easy to understand. The relationship between readability and SEO is real, it is just indirect.
For GEO purposes - getting cited by AI systems like ChatGPT and Perplexity - readability matters more directly. AI systems strongly prefer content that is structured clearly and written in direct, declarative sentences. The same writing habits that improve readability (shorter sentences, active voice, clear transitions) also improve AI citability.
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Readability Checker - FAQs
What is a Flesch Reading Ease score?
The Flesch Reading Ease score measures how easy a piece of text is to read on a scale of 0 to 100. Higher scores mean easier reading. Scores of 60 to 80 are considered standard and suitable for most general audiences. The score is calculated using average sentence length and average number of syllables per word - shorter sentences and simpler words produce higher scores.
What is a good readability score for SEO content?
For most web content targeting a general audience, a Flesch score between 60 and 80 is ideal. This corresponds roughly to a Grade 6 to Grade 9 reading level and is accessible to the vast majority of adult readers. If your audience is more specialised - lawyers, doctors, engineers - a lower score and higher grade level is perfectly appropriate.
What is passive voice and why does it matter?
Passive voice occurs when the subject of a sentence receives the action rather than performing it. "The report was written by Sarah" is passive. "Sarah wrote the report" is active. Active voice is more direct, easier to read, and more engaging. Most readability guidelines recommend keeping passive voice below 10 to 15 percent of sentences for general audiences.
What are transition words?
Transition words connect ideas and help readers follow your argument. Examples include however, therefore, furthermore, additionally, and consequently. Content with a good proportion of transition words reads more smoothly because it signals the relationship between ideas rather than leaving the reader to infer connections themselves.
Does readability affect AI citability?
Yes - AI systems like ChatGPT, Perplexity and Google AI Overviews strongly prefer content that is clear, direct and well-structured. The same writing habits that improve readability - shorter sentences, active voice, clear transitions - also make content easier for AI to parse and cite. Use the GEO Content Checker alongside this tool to see both scores together.
Is this readability checker free?
Yes, completely free with no signup required. Everything runs in your browser - no content is sent to any server.