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Readability Checker

Score text with Flesch reading metrics.

Use the Readability Checker tool

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What this readability checker does

Readability Checker calculates Flesch Reading Ease and the Flesch–Kincaid Grade Level from word, sentence and syllable counts. It shows the averages behind the scores so you can see whether long sentences or long words are dragging the result down.

The formulas were designed for English prose and rely on a syllable heuristic. Brand names, technical terms and non-English text can skew them, so treat the score as a guide rather than an absolute judgement of clarity.

Why use it

  • Check whether a guide is pitched at the right reading level.
  • Find out whether long sentences, not vocabulary, are the problem.
  • Compare revisions before publishing.

How to use it

  1. 1Paste at least ten words of English text.
  2. 2Read the two scores and the averages.
  3. 3Shorten sentences or simplify vocabulary where the verdict is difficult.
  4. 4Re-run the check after editing.

Worked examples

Plain instructions

Input

Short sentences with common words

Output

A high reading-ease score and a low grade level.

Dense technical paragraph

Input

Long sentences with multi-syllable terms

Output

A lower ease score and a higher grade level, with a longer average sentence length.

Common mistakes

  • Optimising for the score at the expense of precision.
  • Assuming a lower grade level is always better; legal and technical text may need exact terms.
  • Running the formula on text that is not English.

Frequently asked questions

What score should I aim for?
Around 60–70 is plain English for a general web audience. The right target depends on the reader and the subject.
How are syllables counted?
A heuristic groups vowel patterns. It is close enough for a trend but can be wrong on names and unusual words.
Does it check grammar?
No. It measures sentence length and word complexity, not correctness.
Is the text uploaded?
No. The calculation is local.

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