Readability checker
See Flesch Reading Ease and the Flesch–Kincaid grade for the same draft.
A passage of about 100 words or more gives a steadier score than a single sentence.
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Readability scores
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Both scores use word count, sentence count, and an estimated syllable count. They describe sentence length and word length, not whether the writing is good.
- Syllables (estimate)
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- Words per sentence
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- Syllables per word
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How to use the readability checker
- Paste a passage of English prose. About 100 words or more keeps the score from jumping when you change one sentence.
- Read the ease score and the grade together. The band under each number is an interpretation of the formula, not a second measurement.
- Look at words per sentence and syllables per word if you want to know which ingredient moved.
- Open Flesch Reading Ease or the Flesch–Kincaid grade page for the formula you have to cite.
Same ingredients, two questions
Both formulas use three counts: words, sentences, and syllables. Words and sentences follow the rules on theword counter and the sentence counter. Syllables are an estimate: groups of the vowels a, e, i, o, u, and y, with a silent trailing e, an extra beat for -ed after t or d, and a short override list for words the pattern gets wrong (people, business, idea, create, and a handful of others). The estimate does not cover non-Latin scripts. A digit-only token counts as one syllable, which is a stand-in, not the way a person says “2024.”
Reading Ease, published by Rudolf Flesch in 1948, is206.835 − 1.015 × (words ÷ sentences) − 84.6 × (syllables ÷ words). Higher means shorter words and shorter sentences. The grade level, from the U.S. Navy study by Kincaid and colleagues in 1975, is0.39 × (words ÷ sentences) + 11.8 × (syllables ÷ words) − 15.59. Higher means a later school year. The ease page walks the scale. Thegrade page walks what a grade is allowed to mean.
The sample passage scores about 71.6 on Reading Ease and about 7.1 on the grade formula, using187 words and 12 sentences. Load the sample if you want to see those figures in the tool, then replace the sample with your draft. If you are under 100 words, the note on the result says the score is unstable. A six-word sentence can score above 100 on Reading Ease. That is the formula, not a clipped display.
What neither score can see
The formulas do not know the audience, the cohesion between sentences, or whether a short word is common. “Writ” is short and still obscure. They also do not know that you meant the second sentence as a list. If thesentence counter split on an abbreviation that is not in its shield list, both scores move, because both divide by the sentence count. Fix the boundary, then rescore. Time to read is yet another question: a hard paragraph and an easy paragraph of the same length can share areading time and not share a grade.
Limitations
- English prose only. The syllable estimate assumes Latin letters. Other languages will produce a number that is not the Flesch score a specialist would publish.
- Scores are not clipped to 0–100 or to a school range. A result outside that range is labeled so you can see the raw formula.
- The checker does not rewrite sentences. It will not “simplify” the draft for you.
- Very short text, and text with no sentence boundary the rules recognize, cannot support a serious claim about reading level.
Questions people ask
Which score should I report?
Report the one you were asked for. Reading Ease is a 0–100-style scale where higher means easier. The Flesch–Kincaid grade is a U.S. school-year estimate where higher means harder. They use the same ingredients and they are not interchangeable. Each formula has its own page if you need the scale explained.
Why do the two numbers sometimes seem to disagree?
They weight sentence length and syllables differently, and they point in opposite directions: ease falls as the text gets harder, grade rises. A passage can sit in the “standard” ease band and still show a high-school grade. That is not a bug. Read both labels before you edit.
Are the syllables exact?
No. Syllables are estimated from vowel groups in Latin letters, with a short list of exceptions. A pronunciation dictionary would disagree on some words. The estimate is documented on this page and used the same way on the two formula pages.
Can I use this as a reading-age test for a child?
No. The grade formula was built to describe U.S. Navy training materials, not to place a student. It ignores vocabulary that is rare but short, and it ignores whether the reader knows the subject. It is a draft check, not an assessment.
Does the checker send my essay anywhere?
No. Both scores are calculated in the browser from the text in the box. The essay is not uploaded to be scored.