Readability Calculator
Paste English text or enter word, sentence and syllable counts to get Flesch Reading Ease, Flesch–Kincaid Grade Level and the averages behind them.
Interactive calculator · Method READABILITY-1.0 · Last reviewed: 2026-11-04
Calculate your scenario
Flesch Reading Ease = 206.835 − 1.015 × (words ÷ sentences) − 84.6 × (syllables ÷ words).
Your inputs
Default worked example. Edit the inputs to calculate your scenario.
Default worked example
Ease = 206.835 − 1.015 × 9.5 − 84.6 × 1.2632 = 90.33; grade = 0.39 × 9.5 + 11.8 × 1.2632 − 15.59 = 3.02.
How to use the calculator
Paste the passage (at least about 100 words gives steadier scores), or switch to counts mode and enter words, sentences and syllables you counted.
What the result means
The two-sentence sample averages 9.5 words per sentence and about 1.26 heuristic syllables per word, giving a Reading Ease of 90.3 and a grade level of 3.
Formula and units
Flesch Reading Ease = 206.835 − 1.015 × (words ÷ sentences) − 84.6 × (syllables ÷ words). Flesch–Kincaid Grade = 0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59. In text mode a word is a whitespace-separated token containing a letter or digit; a sentence ends at . ! or ? followed by a space or the end; syllables per word = groups of consecutive vowels (a, e, i, o, u, y), minus one for a silent final e (not after a consonant + “le”), with at least one per word.
Worked examples
Short two-sentence passage: Words (counts mode): 100 words; Sentences (counts mode): 5 sentences; Syllables (counts mode): 140 syllables; Input: text; English text (analysed on this page only): The cat sat on the mat. It was a sunny day, and the children played outside until dinner time..
Example result: Flesch Reading Ease: 90.3; Flesch–Kincaid Grade Level: 3; Words / sentences / syllables: 19 / 2 / 24; Average words per sentence: 9.5; Average syllables per word: 1.26.
Counts of 100 words, 5 sentences, 140 syllables: Words (counts mode): 100 words; Sentences (counts mode): 5 sentences; Syllables (counts mode): 140 syllables; Input: counts; English text (analysed on this page only): The cat sat on the mat. It was a sunny day, and the children played outside until dinner time..
Example result: Flesch Reading Ease: 68.1; Flesch–Kincaid Grade Level: 8.7; Words / sentences / syllables: 100 / 5 / 140; Average words per sentence: 20; Average syllables per word: 1.4.
Limitations and common mistakes
English-only heuristics. The syllable rule miscounts some words (for example “being” and “agree” each count 1) and digits count as one syllable; abbreviations such as “Dr.” end a sentence. Enter your own counts in counts mode for exact figures. A readability score measures sentence and word length only; it is not a measure of comprehension, clarity, accuracy or suitability for a particular reader.
Scoring text that contains headings, bullet lists or tables without end punctuation: each block then merges into one very long sentence and the grade level jumps.
Sources and assumptions
Method READABILITY-1.0; last formula review 2026-11-04. Sources and their supported claims. Calculation methodology.