AI Readability Score Checker

How to Use the AI Readability Score Checker

Paste any text into the input area. The tool instantly calculates 4 readability scores: Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog Index and SMOG Index. Furthermore, it shows word count, sentence count, syllable count, average words per sentence and complex word percentage. All analysis runs in real time as you type. Additionally, copy the full score report to clipboard.

1. Paste textEnter AI-generated or human-written content.
2. Read scores4 readability scores update instantly. Green means easy. Amber means moderate. Red means difficult.
3. Check detailsView word count, sentence count, syllables, average sentence length and complex word percentage.
4. OptimiseShorten sentences and replace complex words to improve scores.
5. Copy scoresCopy the full analysis for documentation or team review.

Understanding the 4 Readability Scores

Flesch Reading Ease (0–100)

Higher scores mean easier reading. Furthermore, 60 to 70 is ideal for general audiences. Academic papers score 30 to 50. Most AI-generated content scores 40 to 60 because models default to longer, more complex sentences.

Flesch-Kincaid Grade Level

The US school grade level needed to understand the text. Furthermore, target grade 8 to 10 for general web content. Blog posts should aim for grade 6 to 8. Additionally, this is the score that YOAST SEO and most CMS readability checkers use.

Gunning Fog Index

Estimates the years of formal education needed. Furthermore, a score of 12 means high-school graduate level. Newspapers target 11 to 12. Technical documentation ranges from 14 to 18.

SMOG Index

Simple Measure of Gobbledygook estimates the education level needed based on polysyllabic words. Furthermore, it is particularly accurate for health and medical content. Scores of 6 to 8 are recommended for patient-facing materials.

Why AI Content Needs Readability Checking

AI models tend to produce text at grade 10 to 14 reading level. Furthermore, this is too complex for most audiences. Studies show that content at grade 6 to 8 reading level gets 36 percent more engagement than grade 12+ content. Additionally, Google's helpful content guidelines favour clear, accessible writing.

After generating content with ChatGPT, Claude or Gemini, paste it here to check the reading level. Furthermore, if scores are too high, ask the AI to simplify. Use the prompt: "Rewrite this at a 6th grade reading level with shorter sentences and simpler words." This typically drops the Flesch-Kincaid grade by 3 to 5 levels.

Readability Score Ranges

How to Improve Readability Scores

Shorten sentences to 15 to 20 words maximum. Furthermore, replace polysyllabic words with simpler alternatives ("use" instead of "utilise", "help" instead of "facilitate"). Break long paragraphs into 2 to 3 sentences each. Additionally, use active voice and concrete nouns as sentence subjects.

The single most effective technique is reducing average sentence length. Furthermore, every 5-word reduction in average sentence length improves Flesch score by approximately 10 points. Split compound sentences at conjunctions (and, but, which, because). Moreover, use transition words to maintain flow between shorter sentences.

Competitor Gap Analysis

Most readability checkers show 1 to 2 scores. Furthermore, no free tool combines all 4 major indices with real-time analysis, complex word count, AI-content-specific guidance and copy-to-clipboard in one interface.

The Readability Formulas

References

1. Flesch, R. (1948). A new readability yardstick. Journal of Applied Psychology, 32(3), 221-233.
2. Kincaid, J.P. et al. (1975). Derivation of new readability formulas. Naval Technical Training Command Research Report.
3. Gunning, R. (1952). The Technique of Clear Writing. McGraw-Hill.
4. McLaughlin, G.H. (1969). SMOG grading: A new readability formula. Journal of Reading, 12(8), 639-646.

Frequently Asked Questions

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