Grammar & Readability Checker
Paste any text to get comprehensive readability scores across 5 major formulas - Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau, and Automated Readability Index. See grade level estimates, reading ease scores, hard-to-read sentences, and actionable suggestions for improving your writing. All analysis is rule-based and runs entirely in your browser - no data uploads, no signup required.
No text to analyze
Paste or type text above to see readability scores, statistics, and suggestions. All analysis is performed locally in your browser.
Why Use Our Readability Checker?
5 Major Readability Formulas
Get scores from Flesch-Kincaid Grade Level, Gunning Fog Index, SMOG Index, Coleman-Liau Index, and Automated Readability Index. Each formula provides a grade level estimate, so you can compare across methods for a reliable overall score.
Comprehensive Text Statistics
See word count, sentence count, character count, paragraph count, unique words, complex word count (3+ syllables), long word count (6+ characters), and average words per sentence. Every metric you need for detailed text analysis.
Actionable Suggestions
Get targeted tips based on your text: hard-to-read sentences flagged, complex word density warnings, syllable density analysis, and readability improvement ideas. The suggestions panel helps you identify exactly what to fix.
100% Local & Auto-Saved
Your text is automatically saved to your browser's localStorage. All analysis is rule-based and runs entirely on your device - nothing is sent to any server. No signup, no uploads, no privacy concerns.
Common Use Cases for Readability Checker
Writers & Editors
Writers use the readability checker to ensure their content is accessible to their target audience. A blog post aimed at a general audience should target grade level 8 or below, while academic writing may target higher levels. Instant scores help adjust sentence length and word choice on the fly.
Content Marketing & SEO
Content marketers optimise web copy for both readers and search engines. Readable content ranks better and keeps users engaged longer. The Flesch Reading Ease score helps benchmark content against competitors and ensures consistency across blog posts and landing pages.
Educators & Students
Teachers use the readability checker to evaluate whether textbooks and handouts match their students' reading levels. Students use it to check their own writing assignments - ensuring essays and reports are appropriately structured for their audience.
Technical Writers & Documentation
Technical writers ensure documentation and user guides are accessible to non-technical readers. The readability scores help balance technical accuracy with plain language requirements. The hard-to-read sentence counter flags overly complex instructions.
Business & Professional Communication
Professionals check emails, reports, and proposals before sending them. A well-written email with a low grade level is more likely to be read and understood quickly. The readability checker helps refine messaging for maximum impact with busy readers.
Non-English Speakers & Translators
English language learners use the checker to assess the complexity of texts they encounter. Translators use it to ensure translated content matches the readability level of the original, maintaining consistency across languages for global audiences.
Understanding the Readability Checker
What is a Readability Checker?
A readability checker is a tool that estimates how easy or difficult a piece of text is to read. It uses established formulas that analyse sentence length and word complexity (syllable count) to calculate the education level required to understand the text. Our readability checkerapplies 5 major formulas - Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau, and Automated Readability Index - to give you a comprehensive picture of your text's readability. All analysis is rule-based and runs entirely in your browser with no data uploads.
How Our Readability Checker Works
- Paste Your Text: Type or paste any text into the input area. The tool works with everything from short paragraphs to multi-page documents. Your text is auto-saved to localStorage so you never lose your work.
- Text Analysis: The tool counts words, sentences, characters, paragraphs, and unique words. It also calculates syllable counts for each word using a rule-based syllable counter that handles common English patterns (silent e, -ed, -es endings, -le endings, and more).
- Score Calculation: Five readability formulas are applied to your text. Each formula produces a grade level estimate. The average across all formulas is displayed as the overall average grade level, giving you a reliable benchmark.
- Review & Improve:Check the suggestions panel for actionable tips based on your text's metrics. Copy the full analysis to share or save for reference.
Understanding the Readability Formulas
- Flesch Reading Ease (FRE): Scores text from 0-100, with higher scores indicating easier readability. Scores 60-70 are considered standard. Uses average sentence length and syllables per word. The most widely used readability formula.
- Flesch-Kincaid Grade Level (FKGL): Converts the Reading Ease score to a U.S. grade school level. A score of 8 means an eighth grader can understand the text. Commonly used by the U.S. Department of Defense and many industries.
- Gunning Fog Index: Calculates grade level based on average sentence length and the percentage of complex words (3+ syllables). Named after Robert Gunning, who developed it for newspaper writing in the 1950s.
- SMOG Index: Developed by Harry McLaughlin, the SMOG (Simple Measure of Gobbledygook) index uses the number of polysyllabic words (3+ syllables) to estimate the years of education needed. Most accurate for texts with 30+ sentences.
- Coleman-Liau Index: Unlike other formulas, CLI relies on character count rather than syllable count, making it easier to automate. Uses average characters per word and average sentences per 100 words.
- Automated Readability Index (ARI): Another character-based formula that produces a grade level. Uses characters per word and words per sentence. Designed to work well with automated text analysis systems.
Privacy & Accuracy
This readability checker runs entirely in your browser. Your text is never uploaded to any server - all calculations are performed locally using rule-based algorithms. Text is saved to your browser's localStorage for convenience and can be cleared at any time.
Accuracy note: Readability formulas provide estimates based on surface-level metrics (sentence length and word complexity). They do not account for content clarity, organisation, or reader background knowledge. Use the scores as a general guideline rather than an absolute measure. The syllable counter uses a rule-based approach that handles common English patterns but may not be 100% accurate for all words.
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Frequently Asked Questions About Readability Checker
A readability checker estimates the education level required to understand a piece of text. It uses formulas that analyse sentence length and word complexity (syllable count) to produce grade-level scores. Our tool applies 5 major formulas - Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau, and Automated Readability Index - for a comprehensive assessment.
Simply paste or type your text into the text area. The tool automatically analyses your text and displays statistics and readability scores. You don't need to click any buttons - results update in real-time as you type or paste. All processing happens locally in your browser.
The tool supports 6 measures: Flesch Reading Ease (0-100 scale), Flesch-Kincaid Grade Level, Gunning Fog Index, SMOG Index, Coleman-Liau Index, and Automated Readability Index. Each formula uses a different calculation method, so the average across all scores gives the most reliable estimate.
For general audiences, aim for: Flesch Reading Ease 60-70 (standard), grade level 8 or below. For business communication, grade level 8-10 is common. Academic or technical content may target grade level 12+. The lower the grade level, the more accessible your text is to a wider audience.
The tool uses a rule-based syllable counter that handles common English patterns: vowel groups are counted as syllable cores, silent e endings are handled, special suffixes (-ed, -es, -le, -ism, -asm) are accounted for. While not 100% accurate for all words (it may struggle with loanwords or unusual pronunciations), it provides reliable results for most English text.
Sentences containing more than 20 words are flagged as hard-to-read. Research suggests that sentences of 15-20 words are optimal for readability. Your text should aim for less than 10% of sentences to be flagged. The tool shows both the count and percentage of hard-to-read sentences.
No. All text analysis is performed locally in your browser using JavaScript-based rule algorithms. Your text is never uploaded, transmitted, or stored on any server. It is saved to your browser's localStorage for convenience, and you can clear it at any time using the Clear button.
Yes. Click the "Copy Analysis" button at the bottom of the results section to copy the full analysis (all statistics and readability scores) to your clipboard in a formatted text format. Your text is also auto-saved to localStorage so it persists when you return.