Flesch reading ease
Also called: Flesch-Kincaid, Flesch reading ease score, FRE score
Flesch Reading Ease scores how easy text is to read on a 0 to 100 scale, where higher is easier. It weighs average sentence length and syllables per word. A 60 to 70 score reads as plain English that most 13- to 15-year-olds can follow.
How the score works
The formula is 206.835 minus 1.015 times (words per sentence) minus 84.6 times (syllables per word). Two levers move it: shorter sentences and shorter words push the number up, while long clauses and multi-syllable jargon drag it down.
Rudolf Flesch published the formula in 1948. Its sibling, the Flesch-Kincaid Grade Level (built for the U.S. Navy in 1975), feeds the same inputs into a U.S. school grade instead of a 0 to 100 number. Microsoft Word and most SEO plugins, including Yoast, report one or both.
The bands run roughly like this: 90 to 100 is very easy (about 5th grade), 60 to 70 is plain English a 13- to 15-year-old can follow, 30 to 50 is difficult and college-level, and below 30 is best understood by university graduates.
One caveat worth stating plainly: Google does not use the score as a direct ranking factor. John Mueller has said Google does not count words to compute a reading level and then rank on it. What Google’s helpful-content guidance does ask is whether a page has “spelling or stylistic issues” or looks “sloppy.” Clear writing also keeps readers on the page longer, and that engagement can feed ranking signals indirectly.
How it affects your traffic
Readability is not a lever you pull to rank, but it decides whether a visitor reads past your first paragraph. On-page work treats the Flesch score as one guardrail: a page sitting below 30 on a topic your audience is not academic about tends to lose skimmers before they reach the call to action. We use it as a diagnostic, not a target, and pair it with heading structure, intent match, and internal links so the page earns both the click and the conversion.
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