Readability checker

How to check text readability

1. Paste your article, document, or copy into the input area.
2. The tool calculates readability scores instantly, including Flesch Reading Ease and Grade Level.
3. Review the metrics to understand how easy or difficult your text is to read.
4. Edit your text and watch the scores update in real time.

Common uses

• Checking that web content is accessible to a general audience before publishing, use word counter to check length at the same time
• Simplifying technical documentation to make it readable for non-expert users
• Meeting readability standards for legal, medical, or government documents. The text diff helps compare the original and simplified versions side by side

Technical specification

• Algorithm or formula: Flesch Reading Ease 206.835 - 1.015(words/sentences) - 84.6(syllables/words) (Flesch, 1948); Flesch-Kincaid Grade Level 0.39(words/sentences) + 11.8(syllables/words) - 15.59 (Kincaid et al., 1975).
• Browser API or library: Pure JavaScript; custom syllable counter that counts vowel groups per word, drops silent endings (-e, -ed, -es) and adds a syllable for a consonant plus -le.
• Input limits: No hard cap; metrics work best at 100+ words. Below ~30 words, scores become statistically unreliable.
• Output: Flesch Reading Ease score with a difficulty label, Flesch-Kincaid US grade level, estimated reading time at 150, 238 and 350 wpm, plus word, sentence, character and syllable counts.
• Known limitations: Syllable counting is heuristic and approximate; uncommon words can be misjudged, and each number counts as one syllable. Each Chinese or Japanese character counts as one word, as in the word counter. Scores are calibrated for English text, so no score is shown when the text has only numbers or when most words with letters are in another script.

Frequently asked questions

What readability formulas are used?

The tool calculates Flesch Reading Ease and Flesch-Kincaid Grade Level. Both are based on average sentence length and average syllables per word.

What score should I aim for?

For general web content, a Flesch Reading Ease score of 60 to 70 is ideal. Academic writing typically scores lower, while children's content scores higher.

Is my text sent to a server?

All calculations run in your browser. Our servers are not involved at any point.

How much text do I need for an accurate score?

Readability formulas work best with at least 100 words. Very short texts can produce unreliable scores.