WCAG 3.1.5: Reading Level
A page can pass every technical check and still be unusable if nobody can understand the words. This criterion sets a measurable bar: if your text demands more reading ability than lower secondary education (roughly 7–9 years of schooling), provide supplemental content or a simpler version. It is the closest WCAG comes to a plain-language requirement.
The success criterion, in full
When text requires reading ability more advanced than the lower secondary education level after removal of proper names and titles, supplemental content, or a version that does not require reading ability more advanced than the lower secondary education level, is available.
Two details matter. Proper names and titles are excluded before you assess difficulty — you cannot simplify “Kierkegaard” or a statute’s official name. And the remedy is additive: you may keep the complex original as long as an easier path to the same information exists.
Who this helps
Reading is a stack of skills — decoding letterforms, holding a sentence in working memory, mapping vocabulary to meaning, tracking references across paragraphs. A disability affecting any layer of that stack makes dense prose a barrier as real as a missing ramp.
People with dyslexia and reading disabilities
Decoding costs them far more effort per word, so long sentences and rare vocabulary exhaust the budget before meaning arrives. Shorter sentences and common words leave capacity for comprehension.
People with cognitive and learning disabilities
Nested clauses, abstractions, and implied logic demand working memory and inference. Concrete wording, one idea per sentence, and explicit structure keep the content reachable.
Deaf readers and sign language users
For many Deaf people, the written national language is a second language learned after sign language. Idioms and complex written syntax translate poorly; plain structure translates well.
Non-native speakers and low-literacy readers
About half of adults in many countries read below the level most legal and medical text is written at. Plain language is the difference between completing a task and abandoning it.
The payoff is universal: usability studies consistently show plain language improves speed and comprehension for expert readers too. Nobody has ever complained that a terms-of-service page was too easy to understand.
The lower-secondary benchmark
“Lower secondary education level” comes from UNESCO’s International Standard Classification of Education (ISCED): the stage that begins after roughly six years of primary school and ends about nine years after schooling starts. In US terms that is approximately grades 7–9, ages 12–15. WCAG chose an international education standard rather than any single country’s grade system so the criterion works across languages.
If your text, with proper names and titles set aside, demands more than that, you satisfy the criterion by providing either:
- Supplemental content alongside the original — a plain-language summary covering the key points, illustrations, charts or diagrams of the main ideas, a visual step-by-step guide, or an audio version read aloud.
- An alternative version of the whole content written at lower-secondary level — an “easy read” or plain-language edition, discoverable from the original (a clearly labelled link at the top works well).
There are no exceptions clauses in this criterion — but note the trigger condition does the scoping: text that is already readable at lower-secondary level requires nothing extra, and proper names and titles never count against you.
Pass and fail examples
✓ Passes 3.1.5
- A medical journal article preceded by a plain-language “What this study found” summary.
- An insurance policy page with a linked easy-read version covering every section in simple sentences.
- A tax-filing guide whose complex rules are accompanied by a flowchart and worked visual examples.
- Government legislation published with an official plain-language explainer of what the law means in practice.
- A blog post that scores at grade 8 on Flesch-Kincaid — already below the threshold, nothing extra needed.
✗ Fails 3.1.5
- Terms of service written at postgraduate reading level with no summary or simplified version anywhere.
- A patient-information page dense with unexplained clinical terminology and no plain-language alternative.
- A benefits application whose instructions score at grade 14, with the “help” link leading to equally dense text.
- A one-line marketing summary bolted onto a 5,000-word contract — supplements must cover the substance, not just exist.
Writing to the level (with examples)
The mechanics of plain language are well established: prefer short sentences (aim under ~20 words), common words over jargon, active voice, one idea per sentence, concrete examples, and generous structure — headings, lists, and summaries. Watch the transformation:
✗ Grade ~16 (fails the threshold, needs a supplement):
"Remuneration disbursements shall be effectuated subsequent to
the finalization of the verification procedures referenced in
Section 4.2, contingent upon satisfactory documentation."
✓ Grade ~6 (passes outright):
"We will pay you after we check your documents.
Section 4.2 explains what we check."When the original must stay complex, add a labelled plain-language summary and link the two versions both ways:
<article>
<h1>Data Processing Agreement</h1>
<section aria-labelledby="summary-heading" class="plain-summary">
<h2 id="summary-heading">Summary in plain language</h2>
<ul>
<li>We store your data in the EU.</li>
<li>We never sell your data.</li>
<li>You can ask us to delete it at any time.</li>
</ul>
<p><a href="/legal/dpa-easy-read">Read the full easy-read version</a></p>
</section>
<section aria-labelledby="full-heading">
<h2 id="full-heading">Full legal text</h2>
<!-- the unavoidable legal language lives here -->
</section>
</article>Supplements do not have to be prose. A diagram often outperforms a rewritten paragraph — pair it with a text alternative so it stays accessible:
<figure>
<img src="/img/claims-process.svg"
alt="How a claim works: 1. You send the form.
2. We check it within 5 days. 3. We pay you." />
<figcaption>The three steps of a claim, illustrated.</figcaption>
</figure>
<audio controls src="/audio/claims-guide.mp3">
<a href="/audio/claims-guide.mp3">Listen to this guide (MP3)</a>
</audio>How to test with readability scores
- 1
Extract the text and strip proper names and titles
Copy the main content of the page. The criterion tells you to remove proper names (people, places, products) and titles (of documents, laws, works) before assessing — they are unavoidable and inflate scores unfairly.
- 2
Run a readability formula appropriate to the language
For English, Flesch-Kincaid Grade Level is the standard: a score of about 9 or below approximates lower-secondary level (Flesch Reading Ease roughly 60 or higher). SMOG, Gunning Fog, and Coleman-Liau are useful cross-checks; other languages have adapted formulas (e.g. Flesch-Douma for Dutch, Fernández-Huerta for Spanish).
- 3
Score representative passages, not just the intro
Introductions are usually the friendliest text on the page. Sample the dense middle sections — eligibility rules, technical procedures, legal clauses — because that is where the criterion is failed.
- 4
If any passage exceeds the level, look for the remedy
Check whether supplemental content (plain summary, diagrams, audio) or a full lower-secondary alternative version exists and actually covers the same information. A supplement that omits the substance does not count.
- 5
Sanity-check with humans
Formulas count syllables and sentence lengths; they cannot detect ambiguity, idiom, or missing context. Ask someone unfamiliar with the domain to read the text and explain it back. Plain-language testing with real users is the gold standard.
You can score your copy right now: the Accessible Typography Studio includes a readability analyzer that computes Flesch-Kincaid and related metrics as you paste in text — useful for checking a page against the lower-secondary threshold while you also tune its typography. Then work through the rest of the WCAG 2.2 checklist.
Common failures
- Publishing legal, medical, or financial content at university reading level with no summary, diagram, or easy-read alternative at all.
- Writing a 'summary' that is just the first paragraph of the same dense prose, rather than a genuine plain-language restatement.
- Providing a simplified version that quietly omits obligations, exceptions, or costs — the easy version must carry the same substance.
- Hiding the plain-language version so deep in the footer that the readers who need it never find it.
- Relying on jargon and unexplained acronyms ('per the SLA, RPO targets apply') even in the supposedly simple version.
- Assuming a readability score alone proves comprehension — short sentences full of ambiguity still fail readers, and testers should flag them.
- Treating the criterion as a ban on complexity and refusing to publish necessary technical detail, instead of adding the supplemental path.
Relationship to other criteria
Guideline 3.1 Readable builds up in layers. 3.1.1 Language of Page (A) and 3.1.2 Language of Parts (AA) make sure assistive technology pronounces the words correctly. The AAA tier then addresses whether the words can be understood: 3.1.3 Unusual Words and 3.1.4 Abbreviations require mechanisms to explain jargon and acronyms, 3.1.5 sets the overall reading-level bar, and 3.1.6 Pronunciation handles words whose meaning depends on how they are pronounced.
Reading level also interacts with presentation: text that meets 1.4.12 Text Spacing (AA) and is organized under descriptive 2.4.6 Headings and Labels (AA) is dramatically easier to process for exactly the same readers this criterion protects. Plain words, breathable typography, and honest headings are one project, not three.
Frequently asked questions
What does WCAG 3.1.5 Reading Level require?
When text requires reading ability more advanced than the lower secondary education level — after removing proper names and titles — supplemental content or an alternative version at that level must be available. Lower secondary education corresponds to roughly seven to nine years of schooling (about grades 7–9 in the US, ages 12–15), following UNESCO's ISCED classification. It is a Level AAA success criterion under Guideline 3.1 Readable. Importantly, it does not ban complex text; it requires an easier route to the same information.
Does 3.1.5 mean I have to dumb down technical or legal content?
No. The criterion explicitly allows the main content to remain as complex as its subject demands — a research paper stays a research paper. What it asks is that when the text exceeds the lower-secondary threshold, you add support: a plain-language summary, an abstract written simply, diagrams or illustrations that convey the key points, an audio version, or a separate easy-read edition. Readers who need the simpler path get one; expert readers lose nothing.
How do I measure reading level for 3.1.5?
Use established readability formulas. For English, Flesch-Kincaid Grade Level and Flesch Reading Ease are the most common; SMOG, Gunning Fog, Coleman-Liau, and Dale-Chall are alternatives, and many languages have their own adapted formulas. A Flesch-Kincaid grade of about 9 or below (Reading Ease roughly 60+) approximates the lower-secondary benchmark. Remove proper names and titles first, as the criterion instructs, since you cannot simplify someone's name. Formulas are estimates — pair the score with human review.
What counts as 'supplemental content' under 3.1.5?
Anything that helps a reader who struggles with the original text reach the same information: a short plain-language summary at the top of the page, charts, infographics or illustrations of the main points, a step-by-step visual walkthrough, a glossary of the difficult terms, an audio recording of the content read aloud, or a full alternative easy-read version linked prominently. The supplement must cover the substance of the content, not just restate the headline.
Does 3.1.5 apply to every page on a site?
It applies to text content that requires reading ability beyond lower secondary level. Short navigation labels, product names, and simple UI copy usually sit below the threshold already. The pages that typically trigger it are dense ones: terms of service, medical and financial explanations, government guidance, insurance policies, and long-form technical documentation. For conformance claims, remember that AAA criteria are assessed per page — each page with complex text needs its supplement or alternative.
Who benefits from meeting 3.1.5?
People with reading disabilities such as dyslexia, people with cognitive and learning disabilities, people with memory or attention impairments, Deaf readers for whom written language is a second language after sign language, readers with lower literacy, and anyone reading in a non-native language. That last group alone is enormous — plain language consistently improves comprehension, task completion, and satisfaction for all readers, which is why governments increasingly mandate it regardless of WCAG.
Related Success Criteria
The default human language of each page can be programmatically determined.
The human language of each passage can be programmatically determined.
A mechanism is available for identifying specific definitions of words.
A mechanism for identifying the expanded form of abbreviations is available.
A mechanism is available for identifying pronunciation of words.