Readability Score — Flesch-Kincaid

What is Readability Score — Flesch-Kincaid?

Readability Score is a free, in-browser tool that tells you how hard or easy your writing is to read. It runs the Flesch Reading Ease formula, which returns a number from 0 to 100 where higher means simpler prose, and the Flesch-Kincaid Grade Level, which estimates the US school grade a reader needs to understand the text. Writers, editors, teachers, content marketers, and UX writers use these scores to keep documentation, blog posts, help articles, and email plain enough for their audience. The tool counts your sentences, words, and syllables, divides them into words-per-sentence and syllables-per-word, and plugs those into the formulas. Syllables are estimated with a vowel-group heuristic rather than a dictionary, so totals are close approximations, not exact phonetic counts, which is what these readability formulas were designed around. Because the widget renders only with JavaScript, this text is the indexable description: check the reading ease of an article, find its grade level, and count syllables, words, and sentences.

How to use Readability Score — Flesch-Kincaid

1. Type or paste the text you want to grade into the Text box.
2. Read the Flesch Reading Ease score, a 0-100 value where higher means easier to read.
3. Read the Flesch-Kincaid Grade Level, the approximate US school grade needed to follow the text.
4. Check the syllable, word, and sentence counts that the formulas are based on.
5. Read the interpretation hint to see the reading band and target audience.
6. Edit your text and watch every score update live, then aim for shorter sentences and words to raise the ease score.

Examples

The cat sat on the mat. It was a warm day.

Reading Ease ~100, Grade ~0 (very easy)

The aforementioned methodology necessitates a comprehensive evaluation of interdependent variables.

Reading Ease ~3, Grade ~17 (very difficult)

Readability matters.

2 words, 1 sentence, ~6 syllables

Frequently asked questions

What is the Flesch Reading Ease score?

It is a 0-to-100 number that estimates how easy text is to read: 90-100 is very easy (around 5th grade), 60-70 is plain English, and below 30 is very difficult, college-level prose. It is calculated from the average sentence length and the average number of syllables per word, so shorter sentences and shorter words raise the score.

What is the Flesch-Kincaid Grade Level?

It converts the same sentence-length and syllable data into a US school grade. A score of 8.0 means an average eighth grader should understand the text. Most general-audience writing aims for grade 7 to 9; lower numbers mean broader accessibility.

How are syllables counted?

Syllables are estimated with a heuristic that counts vowel groups and adjusts for common silent endings such as a trailing e, rather than using a pronunciation dictionary. This gives close approximations that match how the Flesch formulas were tuned, but it can be off by one on unusual or non-English words.

Does it work for languages other than English?

The Flesch and Flesch-Kincaid formulas were designed for English, and the syllable heuristic targets English spelling. The word and sentence counts still work for many languages, but the ease and grade scores are only meaningful for English text.

Is my text uploaded to a server?

No. All counting and scoring runs 100% client-side in your browser using plain JavaScript. Nothing you type is uploaded, stored, or sent anywhere, so you can safely score private drafts, confidential reports, or unpublished articles.