# Readability

Category: [On-Page & Content](https://seo-geo-glossary.com/en/glossary/category/on-page-content/) › [Content quality](https://seo-geo-glossary.com/en/glossary/category/on-page-content/content-quality/) · Also known as: readability score

**Readability** describes how easily readers can understand a written text. It depends on vocabulary and sentence structure, and sometimes also on presentation such as font size and line spacing. A readability score is a number calculated from features of the text, most often word length and sentence length.

## How is readability measured?

The best-known formula is the Flesch Reading Ease: 206.835 minus 1.015 times the average sentence length in words, minus 84.6 times the average number of syllables per word. Higher scores mean easier text. According to reports, a range of 60 to 70 counts as standard plain English, and scores below 30 as very difficult. The Flesch-Kincaid grade level (1975) converts similar inputs into a US school grade. These formulas were developed for English.

Wikipedia cites experts who warn that simple formulas can be misleading. Shortening words and sentences to move a score can make a text harder to understand. A score is a rough check.

## What does readability mean for SEO?

Google's documentation does not name a readability score as a ranking factor. Its guidance on helpful content asks whether a text has spelling or stylistic issues and whether it looks sloppy or hastily produced. For accessibility, WCAG success criterion 3.1.5 (level AAA) asks for supplemental content or a simpler version when text needs a reading level above lower secondary education.

## Example

A guide on redirects uses sentences of 35 words with three subordinate clauses. After splitting them into short sentences and explaining each technical term once, the score rises and the content stays the same.

## FAQ

**What is a good readability score?** For general web content, a Flesch Reading Ease of 60 to 70 is a common target. The right level depends on the audience.

**Is readability the same as legibility?** Legibility concerns how easily characters can be recognized. Readability concerns how easily the text can be understood.

## Related terms

- [User experience (UX)](https://seo-geo-glossary.com/en/glossary/user-experience/index.md)

## Sources

- [Readability – Wikipedia](https://en.wikipedia.org/wiki/Readability)
- [Creating helpful, reliable, people-first content – Google Search Central](https://developers.google.com/search/docs/fundamentals/creating-helpful-content)
- [Reading Level (SC 3.1.5) – W3C WCAG 2.2](https://www.w3.org/WAI/WCAG22/Understanding/reading-level.html)

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Last updated: October 7, 2026
URL: https://seo-geo-glossary.com/en/glossary/readability/