Analyze text readability with Flesch, Gunning Fog, SMOG, and more readability scores.
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About this tool
The Reading Level Checker calculates five industry-standard readability formulas on any text you paste in, giving you a comprehensive picture of how easy or difficult your writing is to understand. Flesch Reading Ease scores from 0 (very difficult) to 100 (very easy). Flesch-Kincaid Grade Level, Gunning Fog Index, SMOG Index, and Coleman-Liau Index each output an approximate US school grade level. The tool also shows word count, sentence count, syllable count, average words per sentence, and average syllables per word — the raw numbers behind the formulas. Each score is accompanied by a plain-English difficulty label (Very Easy, Easy, Fairly Easy, Standard, Fairly Difficult, Difficult, Very Confusing) and an estimated reader age range. Ideal for writers, educators, content marketers, and UX researchers.
How to use
1Paste your text into the input area.
2Scores and counts update automatically as you type or paste.
3Check the Flesch Reading Ease gauge for an overall difficulty rating.
4Read the grade level estimates from each of the five formulas.
5Use the difficulty label and age range to gauge your audience fit.
6Edit your text to shorter sentences or simpler words to improve the scores.
Frequently Asked Questions
The Flesch Reading Ease formula produces a score from 0 to 100. Higher scores mean easier reading. A score of 60-70 is considered plain English suitable for a general audience. Scores below 30 are very academic or technical. The formula penalises long sentences and long words (measured in syllables).
The Gunning Fog Index estimates the years of formal education a reader needs to understand the text on the first reading. It counts the percentage of complex words — those with three or more syllables — and the average sentence length. A score of 12 corresponds to US high-school level; scores above 17 are considered difficult for most readers.
The tool uses a heuristic algorithm that counts vowel groups in each word, with adjustments for common silent-e patterns, diphthongs, and short words. It is accurate for most standard English text but may differ slightly from a manual count for unusual or technical words.
No single formula is definitive. Flesch Reading Ease and Flesch-Kincaid Grade Level are the most widely used and cited. Gunning Fog is popular in journalism. SMOG is often preferred for health and medical documents. Coleman-Liau relies on character counts rather than syllables, making it more consistent for digital text. Looking at the consensus across all five gives the best picture.
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