Flesch Reading Ease Calculator

How it is calculated

The tool counts words (W, runs of non-space characters), sentences (S, each run of . ! or ? counts once, minimum 1) and syllables (Y). Syllables are estimated per word as groups of vowels a, e, i, o, u, y, with one subtracted for a silent final e, and at least 1 per word. Then Ease = 206.835 − 1.015 × (W/S) − 84.6 × (Y/W) and Grade = 0.39 × (W/S) + 11.8 × (Y/W) − 15.59.

Only English letters are counted in syllables, so the formulas suit English text. The syllable counter is a heuristic and can be off by one for some words. Very short or very long-worded text can score above 100 or below 0; the scale is not clamped.

Common mistakes

• Pasting non-English text. Syllable detection only looks at English letters and vowels a, e, i, o, u, y, so scores for other languages are not meaningful.
• Expecting every score to stay between 0 and 100. Very simple text can exceed 100, and dense text can go far below 0.
• Using decimals, URLs or abbreviations like 3.14 or e.g. in the text. Every run of . ! or ? counts as a sentence end, which inflates the sentence count and the ease score.
• Testing a headline or a few words. With one sentence the averages swing wildly; use at least a paragraph.
• Believing a high ease score means good writing. It only measures sentence length and word length, not clarity, accuracy or structure.