Readability Checker
Analyze words, sentences, estimated syllables, Flesch Reading Ease and Flesch-Kincaid Grade Level for an English draft.
Check English readability with Flesch metrics
Analyze words, sentences, estimated syllables, Flesch Reading Ease and Flesch-Kincaid Grade Level for an English draft.
How the readability checker calculates scores
The calculator uses the classic English-language Flesch Reading Ease and Flesch-Kincaid Grade Level formulas. Both depend on average sentence length and average syllables per word, but their scales are interpreted differently.
Flesch Reading Ease
Reading Ease is calculated as 206.835 − 1.015 × average sentence length − 84.6 × average syllables per word. Higher scores generally indicate easier English prose. The score is a writing diagnostic, not a quality score: specialist material may appropriately require technical vocabulary.
Flesch-Kincaid Grade Level
Grade Level is calculated as 0.39 × average sentence length + 11.8 × average syllables per word − 15.59. It estimates the U.S. school-grade level associated with the text's sentence and word complexity.
Why online readability tools can disagree
The formulas are fixed, but automated tokenization and syllable counting differ. Names, acronyms, URLs, numbers, hyphenated terms and domain vocabulary can produce different counts. This calculator uses a practical heuristic, so treat small score differences as approximate.