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WCAG plain language: what reading level means at AA and AAA

By ValleyFill · November 8, 2026

Do the Web Content Accessibility Guidelines (WCAG) require every web page to use plain language? The precise answer starts with a distinction: Success Criterion 3.1.5, Reading Level, is Level AAA, not Level AA. WCAG 2.1 Level AA conformance includes the A and AA criteria; it does not include every AAA criterion. WCAG 2.2 keeps the same reading-level requirement at AAA. 1 2 4

That is not a reason to set clear writing aside. W3C's accessibility writing guidance recommends simple language, clear instructions, useful headings and meaningful links. This article separates the WCAG plain language question from a practical editorial question: how can your team explain a task without making readers work through unnecessary complexity? 6

What SC 3.1.5 actually asks for

The criterion applies when text requires reading ability beyond the lower secondary education level, after removing proper names and titles. In that situation, supplemental content or a version that does not demand reading ability above that level must be available. It does not simply say that every original document must be rewritten. 1

W3C's Understanding document explains that the aim is to support understanding of difficult text while still allowing complex material to be published. It describes lower secondary education in terms of education ending nine years after primary education begins, rather than naming a universal school grade. Proper names and titles are excluded from the assessment because changing them can obscure what they identify. 3

Consider a technical policy with specialist terminology. As an editorial approach, keep the precise policy available and place an accessible explanation beside it. Explain what the policy means for the reader, what action to take, and where to find detail. W3C lists summaries, illustrations and other supplemental approaches among its techniques for this criterion; the appropriate choice depends on the content. 3

Do not treat that suggestion as permission to remove important conditions. Preserve qualifications and exceptions in the explanation, and have a subject specialist check that the simpler version still communicates the intended meaning.

AA versus AAA: separate the target from the writing goal

WCAG defines conformance levels cumulatively: AA includes A and AA success criteria; AAA adds the AAA criteria. Meeting one AAA criterion does not establish AAA conformance, just as meeting the reading-level criterion does not establish conformance for a whole page. WCAG has other conformance requirements, including requirements for full pages and complete processes. 2

Under Guideline 3.1, Readable, language identification appears at A for the page and AA for passages or phrases, subject to the criterion's exceptions. Unusual Words, Abbreviations and Reading Level are AAA criteria. This is more specific than saying “understandable means everything must be plain English.” 5

Keep two separate lines in your review notes:

For the broader framework, use our accessibility standards guide. For project sequencing, see our Title II planning guide. This explainer addresses a technical distinction, not a conclusion about any organization's legal obligations. Ask qualified counsel about applicable requirements.

Why clear language still matters at an AA target

W3C explains that complex text can create barriers for people with reading disabilities, including people with advanced education or specialist knowledge. Its cognitive accessibility guidance recommends common words, short sentences, small blocks of text and unambiguous content to support understanding. Those recommendations remain useful even when a team's conformance target does not include SC 3.1.5. 3 8

Also distinguish reading level from the words around an interface. WCAG 2.1 has separate requirements for headings and labels to describe their topic or purpose, labels or instructions when input is required, and textual descriptions of automatically detected input errors. These are not interchangeable with a reading-level score. 10

A practical review should therefore ask both “What does this page explain?” and “Can someone tell what this control will do?” Review the introductory paragraphs, but also the button labels, field instructions, confirmation messages and links.

A practical clear-writing pass for public-sector and web teams

The following workflow is editorial guidance, informed by W3C's writing tips and technique G153. It is not a separate WCAG checklist or a claim that these edits alone establish conformance. 6 7

1. Start with the reader's task

Choose one page and write its purpose in a sentence: “This page helps a reader renew a permit.” Draft an opening that answers the questions needed to begin. Put background information after the action-oriented explanation unless it changes what the reader should do.

Try headings that answer real questions: “What you need before you start,” “How to apply,” and “What happens after you submit.” W3C recommends headings that describe sections and communicate structure. Use actual heading markup, not just bold text. 6

2. Replace complexity without deleting meaning

W3C's G153 recommends familiar words, a single topic per paragraph, consistent labels and simpler sentence forms. Use those suggestions as an editing lens rather than a word-replacement contest. Keep a necessary technical term and explain it instead of substituting a shorter but inaccurate word. 7

Here is an original, fictional example:

Before: “Applicants seeking renewal shall furnish the requisite supporting documentation prior to initiation of processing.”

After: “To renew, send the documents listed below. We will start reviewing your application after we receive them.”

For a real page, replace “documents listed below” with a specific, accurate list. Confirm who receives the documents and when review actually starts. Do not invent a promise while trying to improve a sentence.

3. Make terms and references explicit

Expand unfamiliar abbreviations on first use and consider a glossary for specialist terms, as W3C's writing tips recommend. Use the same name for the same thing throughout the task. 6 7

In your review, circle words such as “it,” “this” and “they.” Check whether the reader can identify the reference without rereading earlier paragraphs. Replace an unclear pronoun with the relevant document, person or action. Prefer “Upload the renewal form” to “Upload it” when several documents have just been mentioned.

4. Break instructions into distinct steps

W3C's cognitive guidance includes separating instructions, while its writing tips recommend clear input requirements and error messages. Turn a dense sequence into ordered steps when the order matters. Put each instruction close to the field or action it explains. 6 8

For a fictional upload form, consider:

  1. Choose the completed application file.
  2. Select “Upload application.”
  3. Check that the file name appears before continuing.

Adapt the wording to the actual interface. If the form rejects a file, identify the problem and explain the supported correction rather than displaying only “Invalid input.” Check those instructions against the implemented behavior.

5. Add a useful explanation for complex material

For a long policy, try a brief summary followed by the full text. Identify who it concerns, the main action, important conditions and where to ask questions. W3C's Reading Level guidance includes readable summaries as a technique, and its cognitive guidance recommends summaries of long documents. 3 8

Treat the summary as maintained content. Assign someone to update it when the underlying document changes. Ask a knowledgeable reviewer to compare the two for missing exceptions or changed meaning. Label a summary as a summary; do not present it as the complete policy.

Readability scores: use a signal, not a verdict

W3C's Understanding document discusses assessing reading ability, including evaluation by qualified teachers against education standards. It also notes that no single text will suit every person with literacy and comprehension difficulties. Its use of reading level provides a testable measure; it is not a promise that all readers will understand the result. 3

As a review practice, use a readability result to locate passages worth examining. Do not approve a page solely because it reaches a chosen score. Check whether it preserves meaning, explains the necessary terms and supports the task. When assessing SC 3.1.5, remember its explicit treatment of proper names and titles rather than treating an unadjusted score as the criterion itself. 1

Invite intended readers to try the revised instructions, where feasible. Ask them to explain the next action in their own words. Record confusing passages and revise them. This is a recommended editorial exercise, not a substitute for evaluating the applicable WCAG criteria.

A sensible next step

Pick one important service page and its associated form. Review the wording alongside headings, labels and error messages, then record what changed and what still needs assessment. W3C's Easy Checks can help begin a broader review, but explicitly warns that those checks are not exhaustive. 9

If you want an automated starting point, ValleyFill's free Snapshot checks a limited set of basic signals. Our audit services are software-only and do not include human cognitive or editorial review; neither is a guarantee of WCAG conformance. Read the scope or contact ValleyFill before choosing a service. Clear writing still deserves its own review.

Sources and further reading

Official sources checked November 7, 2026.

  1. WCAG 2.1, SC 3.1.5: Reading Level.
  2. WCAG 2.1 conformance requirements.
  3. Understanding SC 3.1.5: Reading Level.
  4. WCAG 2.2, SC 3.1.5: Reading Level.
  5. WCAG 2.1, Guideline 3.1: Readable.
  6. WAI: Writing for Web Accessibility.
  7. W3C technique G153: Making the text easier to read.
  8. WAI cognitive accessibility guidance: Use Clear and Understandable Content. Supplemental guidance, not additional WCAG conformance requirements.
  9. WAI: Easy Checks — A First Review of Web Accessibility.
  10. WCAG 2.1: Headings and Labels, 2.4.6, Labels or Instructions, 3.3.2, and Error Identification, 3.3.1.

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General educational information, not legal advice. By ValleyFill.

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