WCAG conformance: what levels A, AA and AAA actually require

Tenders, contracts and legal texts keep repeating the same phrase: the website must be “WCAG conformant”. What hides behind those four letters, which of the three levels A, AA and AAA you actually need and how to get there is what this guide clears up. The short answer first: for almost every business, level AA is the benchmark, because that is exactly what the European Accessibility Act and its national implementations point to. And since theory without a diagnosis is worth little, you can test your website right here before reading on.

What WCAG conformance really means

The Web Content Accessibility Guidelines (WCAG) are the international standard for accessible web content, published by the World Wide Web Consortium (W3C). They translate a big goal, making websites usable for people with visual, hearing, motor or cognitive impairments, into concrete, testable requirements called success criteria. The current version WCAG 2.2 contains 86 such criteria across three levels: 31 at level A, another 24 at level AA and 31 at level AAA.

Conformance is not a feeling and not a self-assessment, it follows one clear rule: a page conforms to a level only when it satisfies every single criterion of that level and all levels below it. AA conformance therefore means all 31 A criteria plus all 24 AA criteria, 55 in total. One genuine violation is enough to break formal conformance. That is exactly why a systematic approach beats cosmetic spot fixes.

WCAG, EN 301 549, EAA: sorting out the terms

Accessibility comes with a pile of acronyms that are constantly mixed up. The hierarchy is simpler than it looks: WCAG is the technical core, everything else is a legal frame pointing at that core.

For practical purposes this means: whoever satisfies WCAG at level AA has covered the technical part of every framework above. The differences sit around the edges, in reporting duties, statements and responsibilities, not in the actual requirements for your website.

The three conformance levels: A, AA and AAA

The levels stack like floors of a building, each higher level includes everything below it. The table gives the overview, then we look at each level in turn.

Level A: the foundation

Level A collects the criteria without which a website is simply unusable for certain groups: alternative text for images, full keyboard operability, captions for recorded video and never conveying information through colour alone. Failing here locks visitors out entirely. That is why level A alone is never considered sufficient anywhere, it is the ticket in.

Level AA: the legal standard

Level AA adds the requirements that shape most users' everyday experience: a contrast ratio of at least 4.5:1 for regular text, headings and labels that describe their purpose, a visible keyboard focus, text that scales to 200 percent and consistent navigation. When a law, a client or a tender demands “WCAG conformance”, this level is practically always what they mean.

Level AAA: the gold plating

Level AAA tightens many requirements considerably, for example to a contrast ratio of 7:1 or sign language videos for audio content. The W3C itself states that AAA is not a suitable target for entire websites, because some content cannot meet it at all. The smart move is picking individual AAA criteria where they cost little, such as generous contrast in your own design system.

Three misunderstandings that get expensive

• “We are 90 percent conformant.” Sounds good, does not exist in WCAG. Conformance is binary: a level is met or it is not. The more useful statement is which criteria are still open, and which ones.
• “Our agency built this accessible back then.” The state back then says nothing about today. Every content update, every new plugin and every redesign can introduce barriers. Conformance has an expiry date when nobody re-checks.
• “AAA is better, so let's target that.” Well meant, unrealistic and required nowhere. Declaring AAA as the overall goal burns budget in low-impact places instead of reaching a clean AA first.

The four principles behind every criterion

All 86 criteria follow four principles, abbreviated as POUR. Understanding them lets you judge situations no literal criterion covers:

• Perceivable: information must reach every sense. Images need text alternatives, videos need captions, colours need sufficient contrast.
• Operable: every function must work without a mouse, users need enough time, and nothing may trigger seizures. The keyboard is the toughest and most honest test here.
• Understandable: language, structure and behaviour must be predictable. Forms explain their errors, navigation stays consistent across pages.
• Robust: the code must be clean enough for browsers and assistive technologies such as screen readers to interpret reliably, today and in future versions.

New in WCAG 2.2: nine criteria, one removal

WCAG 2.2 has been the official standard since October 2023 and brings nine new success criteria, six of them on levels A and AA. They target people with motor and cognitive impairments and are refreshingly practical:

• Consistent help (A): help options such as contact or chat sit in the same place on every page.
• Redundant entry (A): data already entered must not be typed again within the same process.
• Focus not obscured (AA): the keyboard focus must not vanish behind cookie banners or sticky headers.
• Dragging movements (AA): anything done by drag and drop needs a simple-click alternative.
• Target size (AA): click targets measure at least 24 by 24 pixels or keep enough distance from each other.
• Accessible authentication (AA): logins must not demand memorising or transcribing, password managers and paste must work.

Where websites actually fail

How wide the gap between ambition and reality is shows in the WebAIM Million study, which tests the home pages of the one million most visited websites every year. The 2026 result: an average of 56 automatically detectable violations per home page, and rising. Remarkably, 96 percent of all detected errors come from just six categories, and they have been the same for seven years:

1. Low text contrast on 83.9 percent of home pages, by far the most common failure
2. Missing alternative text for images on 53.1 percent of pages
3. Form fields without labels on 51 percent
4. Empty links with no discernible target on 46.3 percent
5. Empty buttons without a name on 30.6 percent
6. Missing document language on 13.5 percent

The good news hides in the same statistic: these six error classes are reliably machine-detectable and among the fastest to fix. Clearing them systematically removes the bulk of visible violations.

Why conformance pays off twice

Accessibility is often treated as a box-ticking exercise, which vastly undersells it. Roughly one in four adults in Europe lives with an impairment that can make digital services harder to use. Add older users, people with temporary limitations such as a broken arm, and everyone operating a phone in bright sunlight. Removing barriers opens your offer to paying customers your competitors lock out.

The second win is visibility: many WCAG requirements overlap almost word for word with what search engines reward. Clean heading structure, descriptive link text, alternative text for images, correct language attributes and fast, robust pages help screen readers and Google crawlers alike. Part of your conformance effort is search engine optimisation you would have paid for anyway.

Six steps to WCAG conformance

The road to conformance follows the same pattern whether you run a small company site or a large shop. The order matters: measure first, then fix deliberately, instead of starting somewhere at random.

1. Measure the status quo: start with an automated scan of your key pages. It finds the machine-detectable violations, shows where they sit in the code and gives you an honest baseline with priorities.
2. Prioritise: fix level A violations first, then AA. And think in templates rather than single pages: one corrected navigation template repairs every page using it.
3. Fix systematically: raise contrast in the design system, add alternative texts, label form fields, make link texts descriptive, keep the keyboard focus visible. Each item is craft, none of it is magic.
4. Test manually: automated checks find many violations, not all. Operate your website once entirely without a mouse, zoom to 200 percent and listen to key pages with a screen reader.
5. Publish an accessibility statement: document the state of conformance, known exceptions and a feedback channel. For many providers this statement is mandatory anyway.
6. Keep at it: every update and every new piece of content can introduce new barriers. A regular automated check preserves the state you worked for.

• All images carry appropriate alternative text, or an empty alt attribute when decorative
• Regular text reaches a contrast ratio of at least 4.5:1
• Every function works without a mouse and the focus stays visible
• Form fields have programmatically linked labels and understandable error messages
• Links and buttons describe their target, no “click here”
• The page declares its language correctly in the HTML
• Content works at 200 percent zoom without horizontal scrolling
• Videos have captions, audio content has a text alternative

Testing properly: automated, manual and with real users

A widespread misunderstanding goes: “the scanner finds no more errors, so we are conformant.” Sadly it is not that simple. Automated checks reliably catch the measurable criteria: contrast, missing alternative text, unlabelled fields, language attributes and similar classics. Whether an alternative text is actually meaningful, whether the tab order feels logical or whether an error message truly helps can only be judged by a human.

The sensible division of labour: the automated scan runs first and regularly, because it is fast, cheap and repeatable and uncovers the bulk of violations. Then comes the manual quick test any team can do: operate the whole site by keyboard only, set zoom to 200 percent, listen to core journeys with a free screen reader such as NVDA. For critical flows, say a checkout or a customer portal, add a test with affected users or an external audit. This order saves money: the more the scan clears up front, the less time the expensive manual part burns on the obvious.

Proving conformance: statement and ongoing evidence

Being conformant is one half, being able to prove it is the other. The central instrument is the accessibility statement: a public page describing the state of conformance, naming known limitations honestly and offering a contact channel for barrier reports. It shows market surveillance, customers and clients that you have the topic under control. That requires a current audit behind it, a statement based on a two-year-old test convinces nobody. Treat testing, fixing and declaring as an ongoing process rather than a one-off project and you stay on the safe side permanently.

Frequently asked questions about WCAG conformance

WCAG conformance is not black magic, it is a sequence of well-understood moves: measure, prioritise, fix, test, declare, repeat. You can take the first step in the next two minutes, the scan at the top of this page is waiting.