Readability checker
Analyze text clarity, reading difficulty, grade level, and keyword usage locally in your browser.
What does a readability checker measure?
This checker counts words, sentences, and paragraphs, then calculates average sentence length, Automated Readability Index (ARI), Flesch Reading Ease, and Flesch-Kincaid Grade Level. It also reports keyword density and the ten most frequent non-stopwords.
How the readability scores work
ARI uses character count, word count, and sentence count to estimate a U.S. grade level. Flesch Reading Ease and Flesch-Kincaid Grade Level use word and sentence counts plus estimated syllables. The ARI result is treated as the primary approximate grade signal on this page; none of these formulas is a direct measure of writing quality.
Keyword analysis
The optional keyword field counts case-insensitive, whole-phrase occurrences and divides that count by total words. There is no confirmed ideal keyword density that guarantees search performance. A 1–2% figure is a historical loose guideline, not a confirmed Google ranking factor, so use the metric as a descriptive check rather than a target to maximize.
Limitations
Syllables are estimated with a simple English vowel-group heuristic and can be wrong for irregular spellings, names, abbreviations, and non-English text. Readability formulas are approximations and should be interpreted alongside the actual audience and subject matter.
Frequently asked questions
Which readability score should I use?
The tool shows ARI, Flesch Reading Ease, and Flesch-Kincaid Grade Level. ARI is used as the primary approximate grade signal here, while the other scores provide additional context.
How accurate is syllable counting?
Syllables are estimated with a simple vowel-group heuristic. It works reasonably for many English words but can be wrong for irregular spellings, names, abbreviations, and non-English text.
What is an ideal keyword density?
There is no confirmed Google ranking factor that defines an ideal keyword density. A 1–2% figure is sometimes cited as a historical loose guideline, not a validated ranking target.