WCAG is the international standard, written by the W3C, that says what makes web content usable by disabled people, set out as testable success criteria at levels A, AA and AAA. Its full name is Web Content Accessibility Guidelines. The current version is WCAG 2.2, and level AA is what laws, buyers and courts usually expect.
That one sentence covers the full form, the meaning and the purpose. The rest of this hub explains who writes the guidelines, how they are organised, which version applies to you and how to start using them without reading a long technical document cover to cover.
Quick facts
Full form
Web Content Accessibility Guidelines.
Published by
The W3C, through its Web Accessibility Initiative (WAI).
Current version
WCAG 2.2, a W3C Recommendation since October 2023, with 86 success criteria.
Usual target
Level AA. Under 2.2 that means meeting 55 criteria.
Pronunciation
Most practitioners say "wuh-cag". Some spell out the letters.
Cost to read
Free. The standard and its supporting documents are open on the W3C site.
What is WCAG? Full form and meaning
The four letters are short for Web Content Accessibility Guidelines. Despite the word "web", the guidelines are used for far more than websites: web apps, mobile apps, PDFs, electronic documents and software interfaces are all judged against them in contracts and law. People search for WCAG guidelines, WCAG standards and WCAG rules; all three mean the same document.
The meaning of WCAG in practice is a shared definition of "accessible". Without it, a designer, a developer, a lawyer and a blind user would each have a different idea of what is good enough. With it, a tester can point to a numbered criterion such as 1.4.3 and say exactly what failed and why.
The guidelines are technology neutral. They say what the outcome must be, for example that every function works from a keyboard, not which code to write. Code advice lives in separate supporting documents.
Who publishes the WCAG standards
The World Wide Web Consortium (W3C) is the standards body that also looks after HTML and CSS. Its Web Accessibility Initiative (WAI) runs the working group that drafts WCAG. Drafts go through public review, and the final text becomes a "W3C Recommendation", which is the W3C name for a finished standard.
WCAG 2.0 was also adopted by ISO as ISO/IEC 40500, which is why some government rules quote the ISO number instead of the W3C name. The official home of the standard is the W3C WCAG overview, and the full text of the current version is at w3.org/TR/WCAG22.
How to pronounce WCAG: most people in the field say "wuh-cag", rhyming with "bag". Saying the four letters aloud is also understood everywhere.
How the guidelines are organised
WCAG is built in layers. Only one layer, the success criteria, decides whether a page passes. The rest explain and help.
| Layer | How many in 2.2 | Example | Required? |
|---|---|---|---|
| Principles | 4 | Perceivable | No, they group the guidelines |
| Guidelines | 13 | 1.4 Distinguishable | No, they state goals |
| Success criteria | 86 | 1.4.3 Contrast (Minimum) | Yes, these are what you test |
| Conformance levels | 3 | A, AA, AAA | You choose a target level |
| Sufficient techniques | Hundreds | Using the alt attribute on img | No, one known way to pass |
| Failures | Dozens | Using only color to show an error | No, but each one means a fail |
| Understanding documents | One per criterion | Understanding Contrast (Minimum) | No, informative only |
The four principles are known by the acronym POUR, from Perceivable, Operable, Understandable and Robust. Our page on the WCAG principles walks through each one and the guidelines it holds.
Two smaller details trip people up. Each criterion has a short name and a number, such as 2.4.2 Page Titled, which asks for a descriptive page title, and 3.2.1 On Focus, which bans surprise changes when an element simply receives focus. And there is no official WCAG score: a percentage from a scanning tool is that vendor's own metric, not a W3C measure.
Conformance levels in brief
Every criterion carries one level. Level A covers the barriers that block people outright. Level AA adds the issues that make sites hard to use, such as low contrast and invisible focus. Level AAA is the strictest and W3C does not recommend demanding it for whole sites, because some content cannot meet it.
To claim a level, every full page must pass all criteria at that level and the levels below it. Partial credit does not exist. The guide to levels A, AA and AAA compares them in detail, and the WCAG compliance guide explains what you can honestly claim.
If nobody has told you which level to meet, aim for AA. It is the level nearly every law, policy and tender refers to.
WCAG versions summary
WCAG has grown in steps. Each 2.x release keeps everything from the one before and adds new criteria, so meeting the newest version also covers the older ones (the removed parsing criterion is the only wrinkle).
| Version | Published | Success criteria | AA means | Read more |
|---|---|---|---|---|
| WCAG 1.0 | 1999 | Checkpoints, not criteria | Priority 1 and 2 checkpoints | All versions |
| WCAG 2.0 | December 2008 | 61 | 38 criteria | WCAG 2.0 guide |
| WCAG 2.1 | June 2018 | 78 | 50 criteria | WCAG 2.1 guide |
| WCAG 2.2 | October 2023 | 86 | 55 criteria | WCAG 2.2 guide |
| WCAG 3.0 | Working draft | Outcomes instead | Not defined yet | WCAG 3.0 status |
Most regulations still cite 2.1 AA; our page on 2.1 AA in detail lists those 50 criteria. New projects are better off targeting the 2.2 AA set, which keeps them ahead of the rules.
How laws use WCAG accessibility standards
WCAG itself is not a law. It becomes binding when a law, regulation, court or contract points to it. Treat this as background rather than legal advice: confirm details at the official source and get a lawyer's view on your situation.
| Where | Rule | WCAG reference |
|---|---|---|
| United States, businesses | ADA Title III | No written standard; courts and DOJ settlements usually cite 2.1 AA |
| United States, state and local government | ADA Title II web rule | 2.1 AA, with dates on ada.gov |
| United States, federal agencies | Section 508 | WCAG 2.0 AA, adopted by the refreshed 508 rules |
| EU member states | EAA and Web Accessibility Directive | EN 301 549, which matches 2.1 AA for the web |
| India | RPwD law, GIGW for government sites, SEBI for regulated firms | Aligned with 2.1 AA |
| UK public bodies | Public sector website rules | 2.2 AA plus a published statement |
| Ontario, Canada | AODA | 2.0 AA |
Country by country detail is in accessibility laws, and the US position is covered in ADA website compliance. The W3C keeps a list of web accessibility laws and policies.
The success criteria that fail most
A handful of criteria cause most audit findings. Each has a full guide with tests and fixed code.
| Number | Plain meaning | Level |
|---|---|---|
| 1.1.1 | Every image, icon and image button has a text equivalent | A |
| 1.3.1 | Structure you can see is also in the code | A |
| 1.3.5 | Personal data fields carry the autocomplete attribute | AA |
| 1.4.3 | Regular size text contrast is 4.5:1 or more | AA |
| 1.4.10 | No sideways scrolling at 320 CSS pixels wide | AA |
| 1.4.11 | Borders, icons and focus rings reach 3:1 | AA |
| 2.1.1 | Every feature works with the keyboard alone | A |
| 2.4.3 | Tab order follows the meaning of the page | A |
| 2.4.4 | Link text, with its context, says where it goes | A |
| 2.4.7 | You can always see where keyboard focus is | AA |
| 2.5.8 | Click and tap targets measure 24 CSS pixels square, or have room around them | AA |
| 3.3.1 | Errors are named and described in words | A |
| 4.1.2 | Custom controls expose a name, role and state | A |
| 4.1.3 | Status updates are announced without moving focus | AA |
For the whole list with filters by level and version, use the interactive WCAG checklist.
How to start working with WCAG
You do not need to read the specification in order. This path works for most teams.
- Decide your target. For most organisations that is WCAG 2.2 AA, or 2.1 AA if a law names it.
- Skim the W3C quick reference filtered to level AA to see the full scope.
- Scan key templates with the WCAG checker tools and fix what they find.
- Test by hand: keyboard, zoom, contrast and a screen reader on the main journeys.
- Record results against each criterion in the checklist.
- If you ship an app, follow the mobile app guide as well, since some criteria behave differently on touch screens.
All WCAG guides on this site
Every page in this WCAG section, and what each one answers.
| Guide | Read it for |
|---|---|
| WCAG versions | The full release history and which version is current |
| WCAG 2.0 | The 61 original criteria still named by Section 508 and AODA |
| WCAG 2.1 | The 17 criteria added for mobile, low vision and cognitive needs |
| WCAG 2.1 AA | The 50 criteria behind most current laws |
| WCAG 2.2 | The nine newest criteria and the removal of parsing |
| WCAG 2.2 AA | The 55 criteria to build new projects against |
| WCAG 3.0 | Where the next major version stands and why to wait |
| Levels A, AA, AAA | How the three levels differ and what each demands |
| POUR principles | The four principles and their 13 guidelines |
| WCAG compliance | Conformance requirements, claims and proof |
| WCAG checkers | Free scanners and extensions, and their limits |
| WCAG for mobile apps | Applying the guidelines to native apps |
Questions people ask
What does WCAG stand for?
The letters expand to Web Content Accessibility Guidelines. It is a W3C standard made of testable success criteria describing how to make web content work for disabled people.
How do you pronounce WCAG?
Most accessibility professionals say "wuh-cag", one syllable rhyming with "bag" after a short "wuh". Spelling out W, C, A, G is fine too, and nobody will think it wrong.
Is WCAG a law?
No. WCAG is a technical standard from the W3C. It gains legal force when a law, regulation, court ruling or contract refers to it, which happens in the US, the EU, India, the UK, Canada and many other places.
What is the latest version of WCAG?
WCAG 2.2, which became a W3C Recommendation in October 2023. WCAG 3.0 remains a draft that no law requires.
Is there a WCAG score?
WCAG has no official score. A page either meets a criterion or does not. Percentages shown by scanning tools are each vendor's own way of summarising automated results, which cover only part of the standard.
Does WCAG apply to mobile apps and PDFs?
Its wording targets web pages, yet the principles and most criteria apply to apps and documents too, and laws such as the EU accessibility rules apply them that way. See our guide to WCAG for mobile apps for the differences.