Text Readability Analyzer
Estimate how easy English text is to read with Flesch Reading Ease, Flesch-Kincaid Grade Level and Gunning Fog. See word, sentence and syllable statistics, the formulas used, long sentences and difficult words.
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About the Text Readability Analyzer
Text Readability Analyzer gives a quick estimate of how easy a piece of English prose is to read. It counts words, sentences and characters, estimates syllables, and calculates three widely used scores: Flesch Reading Ease, Flesch-Kincaid Grade Level and Gunning Fog Index. Each formula is shown with your own numbers substituted, so you can see exactly how a score was reached.
Syllables are estimated with a simple, transparent rule (counting vowel groups after dropping a silent final e), and sentence detection handles common abbreviations, initials and decimal numbers. Because these are approximations, every score is labelled as an estimate. Long sentences are highlighted, and long or difficult words can be listed using clearly stated criteria. The formulas are designed for English prose and are less reliable for short texts, lists, code, poetry or other languages. This is not a grammar checker, plagiarism detector or certified assessment.
How to use
- Paste or type English text into the box.
- Choose the sentence length to highlight and whether to list long or difficult words.
- Click Analyze text.
- Review the three scores, the statistics, the formulas and the highlighted long sentences.
- Copy the summary or download it as a .txt file.
Key features
- Flesch Reading Ease, Flesch-Kincaid Grade Level and Gunning Fog Index.
- Word, sentence, character and estimated syllable counts with averages.
- Formulas shown with your numbers substituted.
- Highlighting of sentences longer than a chosen limit.
- Optional list of words with 3 or more estimated syllables or 13 or more letters.
- Copy Summary and Download Summary, with Reset and Back.
Best practices
- Analyse at least a few paragraphs (100 words or more) for steadier scores.
- Remove headings, lists, captions and code before analysing, as they distort sentence counts.
- Use the scores to compare drafts of the same text, rather than as absolute targets.
- Split very long sentences and replace jargon where it does not lose meaning.
- Always read the text yourself — formulas cannot judge clarity, tone or accuracy.
Benefits
- A fast, objective signal of how demanding your writing is.
- Transparent calculations you can check by hand.
- Points to the specific sentences and words worth revisiting.
- Private: your text is analysed in your browser and never uploaded.
Frequently asked questions
How is Flesch Reading Ease calculated?
206.835 − 1.015 × (words ÷ sentences) − 84.6 × (syllables ÷ words). Higher scores mean easier text; plain English writing typically scores around 60–70.
How is the Flesch-Kincaid Grade Level calculated?
0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59. The result roughly corresponds to a US school grade level.
How is the Gunning Fog Index calculated?
0.4 × [(words ÷ sentences) + 100 × (complex words ÷ words)]. Complex words have 3 or more estimated syllables, excluding hyphenated words and not counting -es, -ed or -ing endings. The result is a rough number of years of formal education needed.
How are syllables counted?
With a simple rule: each group of vowels (a, e, i, o, u, y) counts as one syllable after a silent final -e, -es or -ed is dropped, and every word has at least one syllable. It is usually close but not always exact, so the scores are estimates.
Does it work for other languages?
These formulas were developed for English. Text in other languages can be analysed, but the results are unlikely to be meaningful, and a note is shown when much of the text does not use Latin letters.
Does it check grammar or plagiarism?
No. It only estimates readability from sentence length and word length. It does not check grammar, spelling, meaning, tone or originality, and the scores are not a certification.