Paste any text to instantly calculate 5 readability scores — Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog Index, SMOG, and Coleman-Liau. Know exactly how easy or difficult your writing is to understand.
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A readability score measures how easy or difficult a piece of text is to read and understand. Different formulas analyze factors like average sentence length, word complexity, and syllable count to produce a grade-level or numerical score. Using a readability checker helps writers, content marketers, educators, and SEO professionals ensure their writing matches their target audience.
The Flesch-Kincaid Grade Level converts readability into a US school grade equivalent. A score of 8.0 means an average 8th-grade student can understand the text. Most web content targets grade 6–8 for maximum readability. The formula was originally developed for the US Navy in 1975 to assess technical training manuals.
Developed by Robert Gunning in 1952, the Fog Index estimates how many years of formal education a reader needs to understand your text. Business writing typically targets a Fog score of 10–12. A score above 17 suggests your text requires graduate-level reading ability.
Google's ranking algorithms favor content that users find easy to engage with. Studies of top-ranking pages consistently show an average Flesch Reading Ease score of 60–70. High readability reduces bounce rates, increases time on page, and improves overall user experience — all positive SEO signals. WordMetrics' readability checker helps you optimize content before publishing.