Readability Score

What is a readability score?

A readability score is a number that estimates how easy a piece of text is to read. Formulas analyze sentence length, word length, and syllable count to produce a score. That score maps to a grade level, a reading age, or a scale from "very easy" to "very difficult."^[1]

Readability scores help writers, editors, and content teams check whether their text matches their audience's reading level.

What are the most common readability formulas?

Flesch Reading Ease scores text from 0 to 100. Higher means easier. A score of 60-70 fits a general adult audience. The formula is: 206.835 - (1.015 x average words per sentence) - (84.6 x average syllables per word).^[2]

Flesch-Kincaid Grade Level maps the same inputs to a U.S. school grade. A score of 8 means an 8th-grader could understand it. This is the formula built into Microsoft Word.

Gunning Fog Index estimates the years of education needed to understand a text. It puts extra weight on words with three or more syllables. A score of 12 equals high school level.

SMOG (Simple Measure of Gobbledygook) also estimates required education years. It is widely used in healthcare to check patient-facing materials.

Coleman-Liau Index uses character counts instead of syllables. This makes it easier to compute in automated systems.

Why do readability scores matter for large organizations?

Content teams use readability scores to keep web content accessible. A government agency writing a benefits guide should aim for a 6th-8th grade reading level. Insurance companies explaining policy terms need clear language so customers actually understand their coverage.

Legal and compliance teams rely on readability targets to meet regulations. In healthcare, patient-facing documents often must meet specific reading-level requirements. Financial regulators in some countries require consumer disclosures to use plain language.

IT and development teams encounter readability scoring in their content management tools. Many CMS platforms flag content that falls below a set readability threshold, giving editors a chance to revise before publishing.

For websites with 50,000+ monthly visitors, readability directly affects engagement. Content that is too complex pushes visitors away. According to the Nielsen Norman Group, web users typically scan rather than read. Simpler text gets scanned more effectively.

What do readability scores actually measure?

Readability formulas measure surface features of text. They count sentence length and word complexity. They do not measure:

Comprehension. A text can use short, common words but discuss a topic the reader knows nothing about. It will score well but still confuse the audience.

Layout and design. Dense paragraphs, tiny fonts, and missing headings make text harder to read. Formulas cannot see any of this.

Sentence variety. All short sentences can feel choppy and robotic. The readability score looks fine, but the reading experience suffers.

Cultural context. Word difficulty depends on the reader's background, first language, and domain knowledge. A word that is simple for a native English speaker may be difficult for someone reading in their second language.^[3]

How are readability scores used in practice?

Content audits use automated tools to scan every page and flag those below a target score. This helps teams prioritize which pages need editorial review.

Plain language compliance is common in government. Agencies in many countries require public-facing content to meet readability standards.

SEO tools like Yoast, Hemingway Editor, and Grammarly include readability scoring. Content that is easier to read tends to have lower bounce rates and longer time on page.

Readability scores work best as a flagging tool. They catch text that is likely too complex. But a good score does not guarantee good writing. Human judgment is still needed.

How Askem Helps

For large sites with hundreds of service pages, automated readability scanning saves teams from manually reviewing every page. Quality assurance tools check readability across all pages and flag content that falls below a target reading level. Tools like Askem scan the live site continuously without needing installation, so editors can prioritize which pages need revision. Government agencies, healthcare organizations, and financial service providers use these tools to verify that public-facing content meets required plain language standards.

Sources

1. Klare, G. R. (1974). Assessing readability. Reading Research Quarterly, 10(1), 62-102.
2. Flesch, R. (1948). A new readability yardstick. Journal of Applied Psychology, 32(3), 221-233: https://psycnet.apa.org/record/1949-01274-001
3. Plain Language Action and Information Network (PLAIN) — Federal Plain Language Guidelines: https://www.plainlanguage.gov/guidelines/