What is WCAG?

Of the world's million most visited websites, 95.9 percent have errors on the homepage that violate WCAG — and those are just the errors a machine can find. Yet, "follows WCAG" is often written into quotes and specifications without level or version. The difference between following the guidelines and being able to prove it is greater than most people think.

This overview explains what WCAG actually contains, which level and version apply to you, and how you find out where your website stands. It is based on the standard itself, guidance from Digg, and what we see when we review and build websites.

WCAG, Web Content Accessibility Guidelines, is the international standard for accessible web content. It is developed by W3C, the organization behind the web's technical standards, and specifies with testable requirements what a website or app must meet to function for people with disabilities — visual impairment, hearing impairment, motor limitations, and cognitive difficulties.

The current version is WCAG 2.2. Since 2025, it is also an ISO standard, ISO/IEC 40500:2025. In Sweden and the rest of the EU, WCAG level AA is practically what the law measures you against, via the European standard EN 301 549.

WCAG is developed by a working group within W3C's Web Accessibility Initiative. It is the same organization that standardizes HTML and CSS, and that is why WCAG has become the benchmark almost everywhere laws require digital accessibility.

That WCAG 2.2 was approved as ISO/IEC 40500:2025 in October 2025 changes nothing in substance — the content is exactly the same as W3C's version from October 2023. But it makes it easier for more countries and procuring organizations to formally point to the standard.

For you, it means one thing: WCAG is not an agency's interpretation or an industry recommendation. It is an open, free standard that both you and your supplier can read and check against.

WCAG 2.2 has three layers. Four principles, under them 13 guidelines, and under the guidelines 86 success criteria. It is the success criteria that determine whether a website meets the standard. The principles and guidelines are the structure that makes them understandable.

The four principles:

• Perceivable. All content must be perceivable with more than one sense. Images have text alternatives, videos have subtitles, text has sufficient contrast against the background.
• Operable. Everything must be usable with a keyboard and assistive technology, not just with a mouse or finger. No function may require precise movements or time pressure that cannot be turned off.
• Understandable. Language, navigation, and forms must behave predictably. Errors in a form must be explained so that the user understands how to correct them.
• Robust. The code must be written so that browsers and assistive technologies like screen readers can interpret it correctly, even future versions.

Each success criterion is formulated as a testable statement. An example: regular text must have a contrast ratio of at least 4.5:1 against the background, large text at least 3:1. Either the page meets it or it does not.

The success criteria are distributed across three levels. Each level builds on the previous one — to meet AA, you must also meet all the requirements at level A.

• Level A is the foundation, 31 criteria in WCAG 2.2. Violating them excludes certain users completely. A button that cannot be reached with a keyboard is a typical A error.
• Level AA adds 24 criteria, totaling 55. It is the level the law and most procurements are based on. The contrast requirement above is here.
• Level AAA adds another 31. W3C itself advises against requiring AAA for an entire website, as some content types cannot meet all AAA criteria.

What matters in practice is AA. When a supplier writes "WCAG-adapted" without specifying level and version, you actually know nothing.

The versions build on each other. What applied in 2.0 still applies, and each new version adds criteria.

• WCAG 2.0 came in December 2008 with 12 guidelines.
• WCAG 2.1 came in June 2018 and added one guideline and 17 criteria, mainly for mobile, low vision, and cognitive needs. 78 criteria in total.
• WCAG 2.2 came in October 2023 and added nine criteria. An old criterion, 4.1.1 on code interpretation, was removed because browsers and assistive technologies no longer depend on it.

The nine new criteria in 2.2 address issues that are still common: that the focus indicator must not be hidden behind fixed headers or cookie banners, that clickable areas should be at least 24 × 24 pixels, that what requires drag-and-drop should also be doable with simple clicks, that the user should not have to fill in the same information twice, and that login should not require remembering or copying something without alternatives.

A website that meets WCAG 2.2 also meets 2.1 and 2.0. Therefore, our advice is simple: build towards 2.2 AA now, even if your reporting is still against 2.1.

WCAG is not a law. But two Swedish laws make WCAG the benchmark, via the European standard EN 301 549.

• The DOS law, the law on accessibility to digital public services, has applied since 2019 to authorities, municipalities, regions, and certain publicly funded actors. Digg states that the requirements are met by following EN 301 549 V3.2.1, which is based on WCAG 2.1 level AA.
• The Accessibility Act, which implements the EU Accessibility Directive, began to apply on June 28, 2025. It applies to private companies offering certain products and services to consumers, including e-commerce and banking services. The technical level is practically the same.

EN 301 549 has recently received a new version. According to W3C, the 2026 version is based on WCAG 2.2. It will be the benchmark the law refers to only when the EU formally points it out, and until then, it is WCAG 2.1 AA that applies. This is another reason not to build anything new against a lower level than 2.2 AA.

Who is covered, what exceptions exist, and which authorities exercise supervision we have gone through in The Accessibility Directive 2025: what the law actually requires of you.

The errors are surprisingly predictable. WebAIM annually reviews the homepages of a million websites automatically. In the measurement from February 2026, 95.9 percent had errors against WCAG, averaging 56 per page. Six error types accounted for 96 percent of everything found:

• Text with too low contrast — on 83.9 percent of pages
• Images without alternative text — 53.1 percent
• Form fields without labels — 51 percent
• Empty links — 46.3 percent
• Empty buttons — 30.6 percent
• Pages that do not specify the language they are written in — 13.5 percent

The same six have topped the list for seven years. It says something important: the problem is rarely that the requirements are difficult. It's that no one checks them.

We see the same pattern in our own reviews, with two additions that an automatic measurement does not capture: custom-built components like menus, modals, and carousels that cannot be used with a keyboard, and a graphic profile whose colors were never tested against contrast requirements before they were locked.

An automatic tool provides a good first impression, but it is not enough. The tool finds low contrast and missing alt texts. It cannot determine if an alt text describes the image, if the tab order through the page is logical, or if an error message is understandable.

A reliable review therefore has four parts:

1. Automatic scanning of a representative sample of pages — homepage, templates, forms, checkout, or booking.
2. Manual testing with only a keyboard, and with a screen reader on the most important flows.
3. Content check, as accessibility is determined every time someone publishes an image, a PDF, or a video.
4. A prioritized action list linked to each success criterion, not just a score.

The result should then go into your accessibility statement, which reports what meets the requirements and what remains.

It is cheapest when the requirements are included from the start. When we build websites, colors and contrasts are tested in the design phase, components are designed for keyboard use from the start, and the code is written semantically — with ARIA only where regular HTML is not enough. Correcting afterward almost always costs more.

W3C is working on a successor, WCAG 3, with a new structure and a new way to assess compliance. It is still a draft and is not expected to become a finished standard for several years. WCAG 2 will not be replaced until several years after that.

W3C's own advice is clear: the best way to prepare for WCAG 3 is to meet WCAG 2.2 today.

Web Content Accessibility Guidelines. The standard is developed by W3C.

Level AA. Both the DOS law and the Accessibility Act are based on EN 301 549, which today is based on WCAG 2.1 level AA. Level A is not enough, and AAA is not required.

Not yet in Swedish supervision, where WCAG 2.1 AA is the benchmark. But the new version of EN 301 549 is based on WCAG 2.2, and since 2.2 also meets 2.1, it is the level we recommend building towards.

WCAG 2.2 has 86 success criteria distributed across 13 guidelines and four principles. For level AA, 55 of them must be met. WCAG 2.1 has 78.

Yes. Legal requirements apply to digital services in general, and EN 301 549 applies WCAG's requirements to apps and documents like PDFs.

No. The tools find errors that can be measured mechanically, like contrast and missing alt texts, but not whether the page can actually be used with a keyboard or screen reader. That requires manual testing.

In principle, yes. What matters is how templates and components are built and how content is published, not which system is behind it. However, a CMS can make it easier or harder, for example by forcing alt text upon upload.

Do you want to know where your website stands against WCAG 2.2 AA? Read about how we work with accessibility and WCAG, or download our guide to accessible websites.

• Web Content Accessibility Guidelines (WCAG) 2.2 — W3C, recommendation December 12, 2024. Checked October 2, 2026.
• WCAG 2 Overview — W3C WAI. Versions, ISO/IEC 40500:2025 and EN 301 549. Checked October 2, 2026.
• What's New in WCAG 2.2 — W3C WAI. Checked October 2, 2026.
• WCAG 3 Introduction — W3C WAI. Checked October 2, 2026.
• Digital Accessibility — Digg, Agency for Digital Government. Checked October 2, 2026.
• The WebAIM Million, 2026 — WebAIM, measurement February 2026. Checked October 2, 2026.

The text is provided for informational purposes and is not legal advice. For an assessment of if and how the law applies to you, consult legal expertise.