Readability Score Checker

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What each readability score means

Each score uses a published formula. They all measure sentence length and word length in slightly different ways, so it is normal for them to disagree by a grade or more.

• Flesch Reading Ease: 206.835 − 1.015 × (words per sentence) − 84.6 × (syllables per word). Usually 0 to 100, and higher is easier. Very simple text can score above 100 and very dense text below 0.
• Flesch-Kincaid Grade Level: 0.39 × (words per sentence) + 11.8 × (syllables per word) − 15.59. An approximate US school grade, so 8.0 means roughly that an eighth grader could follow the text.
• Gunning Fog Index: 0.4 × (words per sentence + percentage of complex words). Also a US grade level.
• Automated Readability Index (ARI): 4.71 × (letters per word) + 0.5 × (words per sentence) − 21.43. Uses letters and numbers instead of syllables.
• Coleman-Liau Index: 0.0588 × (letters per 100 words) − 0.296 × (sentences per 100 words) − 15.8. Also letter-based.
• SMOG Index: 1.0430 × √(words of three or more syllables × 30 ÷ sentences) + 3.1291. Designed for samples of 30 or more sentences, so the checker labels it a rough estimate on shorter text and needs at least three sentences to show it.

How to read your results

Flesch Reading Ease is shown with a commonly used interpretation: 90 and above very easy, 80 to 89 easy, 70 to 79 fairly easy, 60 to 69 standard, 50 to 59 fairly difficult, 30 to 49 difficult, and below 30 very difficult. Grade-level scores are shown as an approximate US school grade.

There is no single perfect score. For general web content, many writers aim for a relatively accessible reading level, depending on the audience. Microsoft's Word documentation, for example, suggests a Flesch Reading Ease of 60 to 70 for most standard documents. Specialist, academic and technical writing will often score as harder because necessary terms are long, and that can be fine.

Use the scores to find sentences and words worth a second look, then read the text aloud. Our guide to what counts as a good readability score explains the ranges in more detail, and Flesch Reading Ease explained works through the formula with examples.

How this checker counts

• Sentences: text ending in a full stop, question mark, exclamation mark or ellipsis, and lines such as headings or list items. Decimals, common abbreviations such as "Dr." and "e.g.", initials and web addresses are not treated as sentence endings.
• Words: groups of characters separated by spaces that contain a letter or number. List numbers such as "1." at the start of a line are not counted.
• Syllables: estimated with English spelling rules, including silent final e, -ed and -es endings, common prefixes and suffixes, vowel pairs that are usually pronounced separately, and a list of common exceptions. Every word has at least one syllable. Acronyms such as "SEO" are counted letter by letter. In our own check against 312 hand-counted English words that were not used to build the rules, the estimate matched for about 97% of them.
• Complex words: words with three or more syllables, excluding capitalised names, acronyms, hyphenated compounds and words that only reach three syllables with -ed, -es or -ing, following the Gunning Fog method.
• Paragraphs: blocks of text separated by a line break or a blank line.
• Long sentences: 21 to 30 words are highlighted as long and 31 or more as very long. These are practical thresholds for spotting sentences worth a second look, not rules.
• Reading time: based on 200 words per minute, the same as our word counter.

Limitations

• Readability formulas measure sentence and word length only. They cannot judge meaning, accuracy, structure, tone or whether readers know your vocabulary.
• Syllable counts are estimates. Unusual names, abbreviations, compound words and words borrowed from other languages may be counted differently, so other tools can give slightly different scores.
• Sentence detection is heuristic. Unusual formatting, missing punctuation or pasted text with broken line breaks can change the counts.
• Short samples give unstable scores. The checker needs at least 10 words to show scores and warns you below 100 words.
• The formulas were designed for English. The checker warns you when text looks like another language, and scores for non-English text are not meaningful.
• The "What to improve" suggestions come from fixed rules applied to the numbers. They are not AI-generated advice.

Privacy

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