Readability Checker & Reading Level Analyzer
Check text readability online with Flesch-Kincaid, Gunning Fog, and SMOG scores. Free readability checker with grade level results.
About the Readability Analyzer
The Readability Analyzer is a free, client-side tool that evaluates your text against six established readability formulas. It provides grade-level estimates, reading time calculations, and detailed text statistics—all computed instantly in your browser with no server requests.
Readability is crucial for effective communication. Research shows that most adults read at an 8th-grade level, and the most successful web content targets a 7th-8th grade reading level. Government agencies, healthcare providers, and major publications all use readability formulas to ensure their content is accessible.
Whether you are writing blog posts, marketing copy, technical documentation, academic papers, or emails, understanding your text's readability helps you reach your audience more effectively.
Features
Six Readability Formulas
Flesch Reading Ease, Flesch-Kincaid Grade, Gunning Fog, SMOG, Coleman-Liau, and Automated Readability Index—all in one tool.
Real-Time Analysis
Results update automatically as you type with a 300ms debounce. No need to click a button—just start writing.
Grade Level Estimates
Each formula maps to a U.S. school grade level so you can target the right audience for your content.
Reading & Speaking Time
Estimates reading time (at 200 wpm) and speaking time (at 130 wpm) for presentations and podcasts.
Detailed Text Statistics
Word count, sentence count, paragraph count, syllable count, character count, average word and sentence lengths.
Color-Coded Gauges
Visual progress bars with green (easy), yellow (moderate), and red (difficult) color coding for quick assessment.
How to Use the Readability Analyzer
Enter Your Text
Type directly into the text area or paste content from any source. The analyzer needs at least 10 words to produce meaningful results.
Review the Scores
Six readability formulas are computed automatically. Each shows a score, grade level, and visual gauge. Green indicates easy reading; red indicates difficult text.
Check the Grade Level
The overall grade level averages all five grade-based formulas. For general audiences, aim for Grade 7-8. For academic writing, Grade 12+ may be appropriate.
Optimize Your Writing
To lower the grade level: shorten sentences, replace complex words with simpler alternatives, break long paragraphs into shorter ones, and use active voice.
Understanding the Readability Formulas
Flesch Reading Ease (1948)
Formula: 206.835 - 1.015 × (words/sentences) - 84.6 × (syllables/words)
The most widely used readability formula. Scores range from 0 (extremely difficult) to 100 (extremely easy). Developed by Rudolf Flesch, it is used by the U.S. Department of Defense and many state governments for plain language compliance.
Flesch-Kincaid Grade Level (1975)
Formula: 0.39 × (words/sentences) + 11.8 × (syllables/words) - 15.59
Converts the Flesch Reading Ease into a U.S. grade level. Used extensively in education and by the U.S. military to assess readability of training manuals and technical documents.
Gunning Fog Index (1952)
Formula: 0.4 × ((words/sentences) + 100 × (complex words/words))
Developed by Robert Gunning, this index estimates the years of formal education needed to understand text on first reading. "Complex words" are defined as words with three or more syllables.
SMOG Index (1969)
Formula: 3 + √(polysyllable count × 30/sentences)
The Simple Measure of Gobbledygook is considered the gold standard for healthcare materials. It is widely used by the healthcare industry and recommended by the National Institutes of Health (NIH) for patient-facing content.
Coleman-Liau Index (1975)
Formula: 0.0588 × L - 0.296 × S - 15.8 (L = avg letters per 100 words, S = avg sentences per 100 words)
Unlike other formulas, Coleman-Liau uses character counts instead of syllables, making it more reliable for automated analysis where syllable counting may introduce errors.
Automated Readability Index (1967)
Formula: 4.71 × (characters/words) + 0.5 × (words/sentences) - 21.43
Designed for real-time readability assessment. Like Coleman-Liau, it relies on character counts rather than syllables, making it easy to compute and ideal for automated monitoring of content readability.
Related Tools
How to Use Readability Checker & Reading Level Analyzer
Open Readability Checker & Reading Level Analyzer
Navigate to Readability Checker & Reading Level Analyzer in your browser — no installation or sign-up required.
Enter your data
Type, paste, or upload the content you want to process into the input area.
Configure options
Adjust any available settings to customize the output to your needs.
Get your result
The result appears instantly. Copy it to your clipboard or download it as a file.
Frequently Asked Questions
Related Tools
Word Counter
Count words, characters, sentences, and paragraphs online. Free word counter with reading time estimation and keyword density.
Character Counter
Count characters with and without spaces online. Free character counter for Twitter, SMS, titles, and other length-limited content.
Line Counter
Count lines in text online with blank line detection and statistics. Free line counter for code, logs, and text file analysis.
Case Converter
Convert text between uppercase, lowercase, title case, sentence case, and more online. Free case converter for any text format.
String Reverse
Reverse characters, words, or lines in text online. Free string reversal tool for text manipulation and palindrome checking.
Reverse Words
Reverse the order of words in text online. Free word reversal tool that flips word sequence while keeping characters intact.