Readability Checker

How to check the readability of a text

1. Paste your text in the input box. A few paragraphs give a more reliable score than a single sentence.
2. Choose the Text language: English (Flesch) or French (Kandel & Moles).
3. Read the results as they update: the reading ease score, its difficulty, the grade level for English, and the statistics behind them.
4. Look at the Calculation box to see the formula with your own numbers, and at the Longest sentences list to find what to shorten first.
5. Compare your score with the How to read the score table; your band is highlighted.

The Check readability button refreshes the analysis.

The formulas

Both scores combine two measures: the average sentence length (ASL, words per sentence) and the average word length (ASW, syllables per word). Long sentences and long words make a text harder to read.

Flesch Reading Ease (Rudolf Flesch, 1948) gives a score that is usually between 0 and 100. The higher the score, the easier the text:

206.835 − 1.015 × ASL − 84.6 × ASW

Flesch-Kincaid Grade Level (Kincaid and colleagues for the US Navy, 1975) turns the same measures into a US school grade: a score of 8 means an eighth grader should be able to follow the text.

0.39 × ASL + 11.8 × ASW − 15.59

For French, the tool uses the Kandel & Moles formula (1958), an adaptation of Flesch for French, whose words have more syllables on average:

207 − 1.015 × ASL − 73.6 × ASW

Its scores are read on the same 0 to 100 scale. There is no grade level for French, since Flesch-Kincaid was only calibrated on American readers.

For a general audience, aim for 60 or more. Legal, scientific and technical texts often score below 30.

How the text is counted

• Sentences end with a period, question mark, exclamation mark or ellipsis followed by a space, and at each line break, so headings and list items count as sentences. Titles such as “Mr.” or “Dr.”, initials and decimal numbers don’t end a sentence.
• Words are runs of letters or digits; apostrophes and hyphens inside a word keep it whole.
• Syllables are estimated with spelling rules, since there is no dictionary in your browser. In English, the tool counts vowel groups, then handles silent endings (“make”, “jumped”, “boxes”), vowel pairs said as two syllables (“idea”, “radio”, “quiet”), the “y” in “player” and contractions such as “didn’t”. A list of common irregular words, like “people” and “business”, is built in.

In French, the final mute e (and -es) is not counted, as in speech: “table” has one syllable and “école” two. Verbs ending in -ent (“ils parlent”) are recognized, while words like “moment” or “souvent” keep their last syllable. A diaeresis splits a vowel group (“naïf”, “Noël”), and the “u” of “qu” and “gu” is silent. These rules are heuristic and some words will be off by one, which changes the score very little on a text of normal length.

How to improve your score

Split long sentences, especially those in the Longest sentences list. Replace long words with shorter ones when the meaning stays the same (“use” rather than “utilize”). Prefer the active voice and remove filler words. The percentage of words with 3 or more syllables shows where the vocabulary is heavy.

A readability score measures form, not meaning: it cannot tell whether your text is clear, well organized or correct. Use it as a signal alongside your own judgment.