Flesch-Kincaid Readability Calculator

How it is calculated

The tool counts words (W), sentences (S) and syllables (Y) in the text you paste. Then Reading Ease = 206.835 − 1.015 × (W / S) − 84.6 × (Y / W) and Grade Level = 0.39 × (W / S) + 11.8 × (Y / W) − 15.59.

How the counting works: a word is any space-separated piece that contains an English letter, so a token made only of digits is not counted. A sentence is each run of . ! ? characters (at least one sentence is assumed). Syllables are estimated by counting groups of consecutive vowels (a, e, i, o, u, y) and dropping one for a silent final e. This is built for English; other languages give unreliable scores. Scores can exceed 100 or go below zero for very simple or very dense text.

Common mistakes

• Testing a single short sentence or a few words; the averages are only meaningful over a paragraph or more.
• Pasting text with decimals, abbreviations or web addresses; every full stop counts as a sentence end, so "3.14" or "e.g." splits sentences and lowers the average length.
• Using the score for non-English text; the syllable estimate is based on English spelling, so Turkish or German passages are not rated correctly.
• Leaving in headings, bullet lists or captions with no ending punctuation; they merge with the next sentence and inflate its length.
• Treating a high Reading Ease as a quality mark; short words and short sentences make the score high even when the writing is vague, and the grade level is a US school-grade scale, not a measure of your readers' age.