Body text should not require post-secondary reading ability
Rule
reading-level· Document, language & navigation · impact minor · Static + live
Why it matters
SC 3.1.5 (AAA) asks that when text demands reading ability beyond lower-secondary education (about 9 school years), a simpler version or summary be available. This rule is a ROUGH SCREEN, not a verdict: on English pages ( starting with "en") with at least 500 characters of paragraph text, it estimates a Flesch–Kincaid grade level using a vowel-group syllable heuristic, and warns once per page when the estimate exceeds grade 12. Readability formulas ignore vocabulary familiarity, structure, and audience — a high score is a prompt to review the writing (or confirm a plain-language alternative exists), never proof of failure. Non-English and short pages are not evaluated.
How to fix
Shorten sentences, prefer common words over jargon, and front-load each paragraph with its main point — or publish a plain-language summary/version alongside the full text. Technical audiences may legitimately need the complex original; the summary satisfies 3.1.5 in that case.
Example
<html lang="en"><body><p>The comprehensive implementation of organizational accessibility remediation methodologies necessitates systematic coordination between interdisciplinary engineering departments, procurement administrators, and institutional compliance stakeholders, particularly when contractual obligations incorporate internationally harmonized regulatory specifications. Furthermore, the quantitative evaluation of conformance documentation requires considerable technical sophistication, because heterogeneous assistive technologies interpret programmatically determinable semantics inconsistently across proprietary rendering implementations.</p></body></html>
<html lang="en"><body><p>We want every person to be able to use this site. The text on each page is short and clear. We use plain words when we can. Each page starts with its main point. Lists break long ideas into small parts. Photos have text that says what they show. Forms tell you what to type in each box. If you get stuck, the help page shows you what to do next. You can also call our team at any time of day. We test the site with real users every month. Their notes help us fix hard words and long lines, and we make the text better each week.</p></body></html>
WCAG success criteria
3.1.5 Reading Level — Level AAA
When text requires reading ability beyond lower-secondary education (roughly 9 school years), a version that does not — or a summary that does not — must be available, so people with reading or cognitive disabilities can understand the content.
Standards
This rule contributes to the following standards:
WCAG AAA