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WCAG is an international standard guideline for web accessibility. The current latest version is 2.2, and the next version, 3.0, is currently being developed.

WCAG 3.0 is still in the Working Draft stage, and it is not expected to be published as an official recommendation until 2028 at the earliest, and possibly even 2030.

WCAG 3.0 is expected to bring significant changes to its content, but we've summarized the major changes from WCAG 2.x.

*The following content is in the draft stage and may be subject to change before being officially recommended.

Changes in structure and terminology

• "Success Criteria" changed to "Outcomes"
• It has a three-layer structure: guidelines, outcomes, and methods.
• As of the current draft, 174 outcomes are defined, a significant increase from 78 in WCAG 2.1 (86 in 2.2) (though this may decrease in the future due to consolidation or deletion).
• The name has changed from "Web Content Accessibility Guidelines" to "W3C Accessibility Guidelines," which now covers more than just "web content" but also apps and other digital products.

Expanding the scope of application

• Focusing on web pages, we are targeting all digital products (Web/App/PDF/ePub/AR/VR/Voice assistants, etc.)
• "Page" has been replaced with "View," and it is compatible with structures that involve screen transitions, such as mobile apps.

Renewal of the evaluation system

• Instead of the traditional A/AA/AAA, a three-level rating system of Bronze/Silver/Gold will be adopted.
• Each outcome was scored on a 5-point scale ranging from 0 (very poor) to 4 (excellent).
• Scoring has been changed to a flexible model that reflects the diverse functional needs of people with disabilities.
• Bronze level is a basic conformance level, roughly equivalent to Level AA of WCAG 2.1
• Silver/Gold builds on Bronze and requires more comprehensive implementation and user evaluation.

Flexibility in conformity assessment

• Compliance can be asserted not only for the entire site, but also for a series of operations such as checkout and money transfer on a process-by-process basis.
• Emphasis on continuous improvement and evaluation in real-world environments
• User-generated content (UGC: posts, comments, photos, videos, etc.) is also taken into consideration

Introducing functional categories

• Classification based on "functional ability" but a "type of disability" (e.g., no vision, limited vision, memory difficulties, etc.)
• Each outcome is associated with a corresponding functional category, and the assessment is also reflected by category.
• Similar to the "functional performance criteria" of Section 508 and EN 301 549

Rear interchangeability

• Not backwards compatible with WCAG 2.x due to significant differences in assessment model scoring
• WCAG 2.2 (A and AA) conformant content is expected to meet many of the minimum (Bronze) requirements of the new standard, but will need to comply with additional new tests and metrics.

Change in the method of calculating contrast ratio (introduction of APCA)

• Instead of the conventional ratio (4.5:1, etc.), the new APCA (Advanced Perceptual Contrast Algorithm) is used.
• Evaluated using the "Lc value (0 to approximately 106)" that takes into account human perception characteristics
• Results vary depending on whether the background is bright or dark (based on the actual human visual perception)
• The Lc value is as follows:
  • Lc 90：Highly readable text (recommended)
  • Lc 75：Regular body text (recommended)
  • Lc 60：Minimum value for normal text
  • Lc 45：Minimum for large text (18pt or larger, bold)
  • Lc 30：The absolute minimum for all text
  • Lc 15：Invisibility threshold (difficult to distinguish)

APCA Features

• Consider font size and weight (thinner text scores lower)
• Swapping the text and background changes the results
• Emphasis on perceptual uniformity of contrast to reflect more realistic readability
• Significantly reduced false positives (in fact, difficult/easy to read) that occurred in WCAG 2.x

For example, a combination of white text on an orange background would often be deemed "NG" under the previous standards (WCAG 2.x) due to insufficient contrast.
However, APCA evaluates images based on the actual human visual perception.If the characters are "large enough and thick enough," they will be judged as OK.This will result in an evaluation that allows for greater design freedom and accessibility.

summary

WCAG 3.0 is a significant evolution from the previous WCAG 2.x, and is expected to be a comprehensive guideline that is more suited to the modern digital environment. However, due to fundamental changes in evaluation methods, it is not backward compatible with WCAG 2.x.

WCAG 2 will not be phased out and will remain in place. Considering that WCAG 2.x is currently adopted as the legal basis in many countries and regions, I feel that WCAG 2.x will remain as the legal basis, and WCAG 3.0 will be used in parallel as the ideal or best practice.

Understanding the direction of changes being considered for WCAG 3.0 will be extremely beneficial and an important guideline when considering future accessibility measures. We are following the development process and preparing to incorporate new ideas.

Reference information:W3C Group Draft Note 04 September 2025