What WCAG is
The Web Content Accessibility Guidelines are a technical standard from the W3C's Web Accessibility Initiative, written to explain how to make web content accessible to people with disabilities. The current version, WCAG 2.2, was published in October 2023 and updated in December 2024, and has also been adopted as an international standard, ISO/IEC 40500:2025. The W3C designed versions 2.0, 2.1 and 2.2 to be backwards compatible: a page that meets 2.2 also meets the earlier two. A third generation, WCAG 3, exists only as an early draft.
Four principles, three levels
Every requirement sits under one of four principles. Content must be:
- Perceivable: people can take it in, whatever senses they use. Text alternatives for images, captions for video and enough contrast belong here.
- Operable: people can use it, whatever input they use. Keyboard access, enough time and no seizure-inducing flashes belong here.
- Understandable: the text and the behaviour are predictable. Labels, clear errors and consistent navigation belong here.
- Robust: it works with browsers and assistive technology such as screen readers, now and as they change.
Under the principles are guidelines, thirteen in WCAG 2.2, and under those the testable success criteria, each with a level. A removes the most basic barriers, AA adds the criteria that policies and laws usually refer to, and AAA is the strictest. A page conforms at a level when it meets every criterion of that level and of the levels below.
Ten checks anyone can do
The W3C's Easy Checks are a first review that needs only a browser. They do not prove conformance, but they find the barriers that appear on most sites:
| Check | What to look for |
|---|---|
| Page title | Every page has a title that briefly describes it and differs from the other pages on the site |
| Text alternatives | Every image has an alt attribute: a description for informative images, alt="" for decorative ones |
| Headings | The page has headings, text that looks like a heading is marked up as one, and the levels make sense |
| Contrast | Normal text has a contrast ratio of at least 4.5:1 against its background |
| Resize text | With text enlarged, everything stays readable and usable |
| Keyboard and focus | Every link, field, button and control can be reached with Tab and operated, and the focus is visible |
| Forms | Every field has a label tied to it, required fields are marked, errors are explained |
| Moving content | Moving content can be paused, and nothing flashes more than three times a second |
| Media | Video and audio have accurate captions and transcripts; automatic captions alone are not enough |
| Structure | With styles and images turned off, the content still makes sense in reading order |
Several have a tool on this site. The color contrast checker measures the ratio against the 4.5:1 minimum for normal text, the heading structure checker lists a page's headings in order so gaps and skipped levels stand out, and the alt text guide covers text alternatives in detail. For data tables, the HTML table generator writes header cells and a caption, which is what screen readers use to announce each cell in context.
What WCAG 2.2 added
WCAG 2.2 added nine success criteria and removed one, 4.1.1 Parsing, which the W3C describes as obsolete. The additions focus on keyboard users, people with motor impairments and people with cognitive disabilities:
| Success criterion | Level | In short |
|---|---|---|
| 2.4.11 Focus Not Obscured (Minimum) | AA | A focused item is at least partly visible, not hidden under a sticky header or a cookie banner |
| 2.4.12 Focus Not Obscured (Enhanced) | AAA | A focused item is fully visible |
| 2.4.13 Focus Appearance | AAA | The focus indicator is large enough and has enough contrast |
| 2.5.7 Dragging Movements | AA | Anything done by dragging can also be done with a simple click or tap |
| 2.5.8 Target Size (Minimum) | AA | Click and tap targets meet a minimum size or have enough space around them |
| 3.2.6 Consistent Help | A | Help is in the same place on every page that offers it |
| 3.3.7 Redundant Entry | A | People are not asked for the same information twice in one process |
| 3.3.8 Accessible Authentication (Minimum) | AA | Logging in does not require solving, recalling or transcribing something |
| 3.3.9 Accessible Authentication (Enhanced) | AAA | Logging in does not require recognising objects or user-supplied images |
Two of them catch many modern sites. Focus Not Obscured fails when a sticky header or a cookie banner covers the element that has keyboard focus. Accessible Authentication fails when a login demands that people remember or transcribe something, such as a puzzle; allowing password managers to fill the field and allowing paste are the common fixes.
Where the law comes in
WCAG itself is a technical standard, not a law; laws and policies point to it. One example in the United States: the Justice Department's 2024 rule under Title II of the Americans with Disabilities Act requires state and local governments to make their web content and mobile apps meet WCAG 2.1 Level AA. According to ADA.gov, governments serving 50,000 people or more must comply by April 26, 2027, and smaller ones and special districts by April 26, 2028. Private organisations and other countries are covered by other rules; which ones apply depends on who you are and where you operate.
A practical order of work
- Run the ten Easy Checks on your three most visited pages and on any form.
- Fix contrast, alt text, headings and labels first: they are common, quick to fix and help everyone.
- Use only the keyboard: tab through every page and make sure focus is visible and never hidden by a sticky element.
- Check tap target sizes on a phone, and that nothing needs dragging without an alternative.
- Keep pages fast and light; the website speed test shows what slows a page down on older devices and slow connections.
Frequently asked questions
What is WCAG?
The Web Content Accessibility Guidelines, the W3C standard that explains how to make web content accessible to people with disabilities. The current version is WCAG 2.2, published in October 2023 and updated in December 2024; it is also an ISO standard, ISO/IEC 40500:2025. Its requirements are written as testable success criteria, grouped under four principles.
What do levels A, AA and AAA mean?
Each success criterion has a level. A covers the most basic barriers, AA adds the criteria most policies and laws refer to, and AAA is the strictest. A page conforms at a level when it meets every criterion of that level and the ones below it. AA is the usual target; full AAA conformance is rarely required for whole sites.
Is WCAG 2.2 compatible with 2.1?
Yes. The W3C designed 2.0, 2.1 and 2.2 to be backwards compatible, so content that meets 2.2 also meets 2.1 and 2.0. WCAG 2.2 added nine success criteria and removed one, 4.1.1 Parsing, as obsolete.
Is website accessibility a legal requirement?
It depends on who runs the site and where. In the United States, the Justice Department's 2024 rule under Title II of the ADA requires state and local governments to make web content and mobile apps meet WCAG 2.1 Level AA, with compliance dates in 2027 and 2028 depending on population. Other organisations and other countries have their own rules; check the ones that apply to you.
Where do I start?
With the W3C's Easy Checks, ten quick reviews anyone can do in a browser: page title, alt text, headings, contrast, text resizing, keyboard access, forms, moving content, media alternatives and reading order. They do not prove conformance, but they find the most common barriers in an hour.
Sources
- W3C Web Accessibility Initiative: WCAG 2 Overview (WCAG 2.2 published 5 October 2023, updated 12 December 2024; backwards compatible with 2.1 and 2.0; levels A, AA and AAA; four principles; ISO/IEC 40500:2025; WCAG 3 as an early draft)
- W3C Web Accessibility Initiative: What's new in WCAG 2.2 (the nine new success criteria with their levels; 4.1.1 Parsing removed)
- W3C Web Accessibility Initiative: Easy Checks, a first review of web accessibility (page title, text alternatives, headings, contrast of at least 4.5:1, resize text, keyboard and focus, forms, moving and flashing content, multimedia, basic structure)
- ADA.gov: Fact sheet on the 2024 Title II web and mobile app rule (WCAG 2.1 Level AA for state and local governments; compliance dates April 26, 2027 for populations of 50,000 or more and April 26, 2028 for smaller entities)