Web Content Accessibility Guidelines (WCAG) Overview

Web accessibility starts with conformance to the Web Content Accessibility Guidelines (WCAG).  The WCAG are technical standards published by the Web Accessibility Initiative (WAI) of the World Wide Web Consortium (W3C) to make the web more accessible.


There are three primary WCAG versions to consider as we near 2021:

  • 2.0
  • 2.1
  • 2.2

Think of WCAG 2.0 as the classic version.  It is incorporated into many laws and provides for a robust baseline of accessibility.

WCAG 2.1 is the updated, current version.  It is incorporated into laws internationally and helps shore up mobile accessibility.

WCAG 2.2 is an upcoming version with release expected in the summery of 2021.  Originally, November 2020 was the target publication date but the proposed draft still needed to be worked through.

Conformance Levels

WCAG versions can have three conformance levels: A, AA, AAA.

Level AA is the standard adopted by all laws, generally.

Conformance with Level AAA can be impossible in some instances but it’s always great to strive to meet some AAA success criteria.

Success Criteria

Success criteria can be thought of as requirements (i.e., things to do) to meet different levels of WCAG versions.  Here is the number count for each version:

  • 2.0 AA – 38 success criteria
  • 2.1 AA – 50 success criteria
  • 2.2 AA – 58 success criteria (proposed)

It’s important to remember that each successive update works on top of the previous update which means nothing in the previous version has been undone.

To illustrate, WCAG 2.1 AA has 50 success criteria including the 38 from 2.0 AA and 12 new success criteria.  Thus, if you’re WCAG 2.0 AA conformant, there are only 12 additional items to implement.

Laws and Regulations

Below are a few of the laws across the globe that incorporate WCAG.  All incorporate level AA

  • AODA (2.0)
  • Section 508 (2.0)
  • EN 301 549 (2.0)
  • Guidelines for Indian Government Websites (2.0)

EN 301 549 affects and has been adopted by multiple countries.