# WCAG

> The Web Content Accessibility Guidelines — the standard almost every accessibility law and procurement contract points at.

- Category: Process & Methods
- Canonical: https://www.themasterly.com/glossary/wcag

WCAG is the Web Content Accessibility Guidelines, published by the W3C. It matters because almost every accessibility law and procurement requirement in the world points at it rather than writing its own rules.

## The structure, which the vocabulary obscures

Four **principles** — perceivable, operable, understandable, robust. POUR.

Thirteen **guidelines** sit under those principles in WCAG 2.2.

Testable **success criteria** sit under the guidelines, and these are the only things conformance is measured against. A claim to "follow the principles" is not a conformance claim.

Each success criterion carries a level: **A**, **AA** or **AAA**.

## Level AA is the answer

Laws and contracts almost always specify AA. It is the level to plan against, budget for, and claim.

AAA is not meant to be applied to a whole product, and the W3C says as much. A contract committing to AAA across a product is usually a sign that nobody involved read the standard, and it is worth flagging before signing rather than after.

## Versions, and the trap in them

| Version | Published |
|---|---|
| WCAG 2.0 | 11 December 2008 |
| WCAG 2.1 | 5 June 2018 |
| WCAG 2.2 | 5 October 2023 |

Each version **adds** to the previous one. Anything conforming to 2.2 also conforms to 2.1, so the versions are not alternatives.

⚠️ **The trap is which version your obligation names.** EN 301 549, the European standard used for the [European Accessibility Act](https://www.themasterly.com/glossary/european-accessibility-act), currently references **WCAG 2.1**. A European contract may therefore not be asking for 2.2 at all, and building to 2.2 is a choice rather than a requirement. WCAG 2.2 is also ISO/IEC 40500:2025, which is the form some procurement documents ask for.

Check which version the obligation names before scoping the work. The difference is real money.

## What it actually asks for

The criteria most B2B products fail are unglamorous and cheap to fix early.

**Contrast.** 4.5:1 for body text, 3:1 for large text, and 3:1 for interface components and their states. See [color system](https://www.themasterly.com/glossary/color-system), and note that the ratio is measured against the background the element actually sits on rather than against white.

**Keyboard access.** Everything operable by mouse must be operable by keyboard, with a visible focus indicator. This is where a `div` with a click handler fails, and where most custom [dropdowns](https://www.themasterly.com/glossary/dropdown-ui) and [modals](https://www.themasterly.com/glossary/modal-design) fail.

**Names, roles and values.** Assistive technology has to be able to announce what a control is and what state it is in. A styled `div` acting as a checkbox announces nothing.

**Not colour alone.** A state signalled only by colour fails, which is why an error needs an icon or text beside the red.

**Target size.** WCAG 2.2 added a 24 by 24 CSS pixel minimum at AA, with exemptions including links inline in text.

## Where teams get it wrong

- **Treating it as a launch checklist.** Retrofitting conformance costs several times what building to it does.
- **Claiming AAA.** A commitment nobody can hold across a product.
- **Testing with a scanner only.** Automated tools catch a minority of criteria. The rest need a person.
- **Building to 2.2 when the contract names 2.1**, or the reverse, without checking.
- **Contrast checked against white** rather than the real background.
- **Principles quoted in place of criteria.** Conformance is measured one way only.

## Related terms

- [Accessibility Audit](https://www.themasterly.com/glossary/accessibility-audit)
- [Vpat](https://www.themasterly.com/glossary/vpat)
- [Inclusive Design](https://www.themasterly.com/glossary/inclusive-design)
- [Color System](https://www.themasterly.com/glossary/color-system)

## Learn more

- [Accessibility as a B2B SaaS deal blocker](https://www.themasterly.com/blog/accessibility-deal-blocker)
- [UX Audit service](https://www.themasterly.com/services/ux-audit)

## FAQ

**What are the WCAG levels?**

Three: A, AA and AAA. AA is what laws and contracts almost always require, and it is the level worth planning against. AAA is not intended to be met across a whole product — W3C says so explicitly — so a commitment to AAA in a contract is usually a sign nobody read the standard.

**What is the difference between WCAG 2.1 and 2.2?**

WCAG 2.2 was published on 5 October 2023 and adds success criteria on top of 2.1 rather than replacing it. Anything conforming to 2.2 also conforms to 2.1. The practical catch is that EN 301 549, the European standard, still references WCAG 2.1, so a European contract may not be asking for 2.2 at all.

**Is WCAG a law?**

No. It is a technical standard published by the W3C, which laws then reference. Section 508 in the United States, EN 301 549 in Europe and most procurement policies point at WCAG rather than restating it, which is why one standard sits behind a great many different legal obligations.

**What are the four principles of WCAG?**

Perceivable, operable, understandable and robust, usually shortened to POUR. Thirteen guidelines sit under those four principles, and the testable success criteria sit under the guidelines. Conformance is measured against the success criteria, never against the principles.

**Does WCAG apply to native mobile apps?**

Not directly, since it is written for web content, but WCAG2ICT describes how to apply it to non-web software and documents, and procurement routinely asks for it anyway. In practice a native app is evaluated against the same criteria with the web-specific wording set aside.

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