Which four principles organize the WCAG criteria?

The four principles are perceivable, operable, understandable, and robust, known by the acronym POUR. Every success criterion can be assigned to exactly one of these principles.

What do conformance levels A, AA, and AAA mean?

Level A covers the most basic requirements, level AA builds on it and is the legally required standard in the EU, and level AAA is the highest, voluntary level that is not fully achievable for all content types in practice.

How can I check whether my website meets the WCAG criteria?

Automated tools such as easyMonitoring test websites against the WCAG criteria and provide prioritized recommendations. A manual review is also recommended, since some criteria leave room for interpretation.

Which four principles organize the WCAG criteria?

The four principles are perceivable, operable, understandable, and robust, known by the acronym POUR. Every success criterion can be assigned to exactly one of these principles.

What do conformance levels A, AA, and AAA mean?

Level A covers the most basic requirements, level AA builds on it and is the legally required standard in the EU, and level AAA is the highest, voluntary level that is not fully achievable for all content types in practice.

How can I check whether my website meets the WCAG criteria?

Automated tools such as easyMonitoring test websites against the WCAG criteria and provide prioritized recommendations. A manual review is also recommended, since some criteria leave room for interpretation.

A person looking at a checklist with checkmarks on a tablet, symbolizing WCAG criteria review

WCAG Criteria Overview: The 4 Principles Explained Simply

Q: What are WCAG criteria?

WCAG criteria are testable requirements from the Web Content Accessibility Guidelines that define when web content counts as accessible. WCAG 2.2 includes a total of 87 such success criteria.

Q: What is new in WCAG 2.2 compared to WCAG 2.1?

WCAG 2.2 adds nine additional success criteria, primarily benefiting users with motor or cognitive impairments, such as minimum target sizes, visible keyboard focus, and low-barrier authentication.

WCAG criteria look technical and overwhelming at first glance. In reality, they break down into four clear principles that every accessible offering must meet.

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Law & BFSG
WCAG Criteria Overview: The 4 Principles Explained Simply

By SiteCockpit

• September 10, 2026 • Law & BFSG • 7 mins read

Summary

WCAG 2.2 comprises 87 success criteria, grouped into four principles: perceivable, operable, understandable, and robust. These criteria are organized into three conformance levels: A, AA, and AAA. For most legal requirements in the EU, including the BFSG, level AA is the mandated standard.

WCAG Criteria Overview: The 4 Principles Explained Simply

Anyone approaching the Web Content Accessibility Guidelines (WCAG) for the first time quickly runs into a confusing number of criteria, levels, and abbreviations. Yet the entire framework breaks down into four clear principles. This overview shows how WCAG criteria are structured, what conformance levels mean, and what matters for businesses.

What are WCAG criteria, exactly?

The WCAG are international guidelines from the World Wide Web Consortium (W3C) that define when web content counts as accessible. The current version, WCAG 2.2, includes a total of 87 success criteria: 61 already existed in WCAG 2.0, 17 were added with WCAG 2.1, and 9 more arrived with WCAG 2.2. Each individual criterion is testable, allowing for objective evaluation rather than leaving room for interpretation.

The four WCAG principles: POUR

All WCAG 2.2 criteria can be assigned to four overarching principles, known by the acronym POUR: Perceivable, Operable, Understandable, Robust.

Perceivable

Content must be perceivable to all users, regardless of which senses they rely on. This includes meaningful alt text for images, captions for videos, and sufficient color contrast. Information must never be conveyed through color alone.

Operable

The user interface and navigation must be operable. All functions must be accessible without a mouse, using the keyboard alone. Users must never be trapped within a component, and enough time must be given to interact with content.

Understandable

Information and the operation of the interface must be understandable. This covers readable language, predictable behavior of elements, and assistance to help avoid and correct input errors.

Robust

Content must be robust enough to be reliably interpreted by a wide variety of user agents, including assistive technologies such as screen readers. Semantically correct HTML is the foundation for this.

Conformance levels: A, AA, and AAA

WCAG criteria are further divided into three conformance levels, reflecting priority:

A Level A: Basic requirements with the highest priority. Without this level, a website has significant barriers.
AA Level AA: Builds on level A and is the legally required standard in the EU, including for the BFSG.
AAA Level AAA: The highest, voluntary standard. Not fully achievable for all content types in practice.

For most legal requirements in the EU, including the German Accessibility Strengthening Act and the European Accessibility Act, conformance level AA is the required standard.

What's new in WCAG 2.2?

WCAG 2.2 was published in October 2023 and adds nine additional success criteria to WCAG 2.1. These primarily benefit users with motor or cognitive impairments, such as minimum target sizes for controls, visible keyboard focus, alternative drag-and-drop mechanisms, and low-barrier authentication. All three WCAG versions are backward compatible: websites meeting WCAG 2.2 automatically meet the earlier versions too.

SiteCockpit Solution

Testing WCAG criteria automatically

Manually checking all 87 success criteria is time-consuming and requires technical understanding of HTML, ARIA, and screen reader behavior. With easyMonitoring, you automatically test your website against the WCAG criteria and receive prioritized recommendations. Since some criteria leave room for interpretation, a manual review usefully complements the automated analysis.

Discover easyMonitoring →

WCAG criteria look complex at first glance, but follow a clear logic: four principles, three conformance levels, one shared goal. Understanding this structure lets you implement accessibility systematically instead of by chance.