What Is WCAG? A Beginner-Friendly Guide
If you’ve spent any time reading about web accessibility, you’ve probably come across the term WCAG — and then immediately felt lost or overwhelmed.
You’re not alone. Most people who care about making their website more accessible hit a wall when they first encounter WCAG because the official documentation reads like a legal standard (because it kind of is one). It is precise, detailed, and written primarily for the people who test and audit websites for compliance.
But, that doesn’t mean you can’t learn and implement the standards on your own content.
WCAG 2.2 is the current version of the standard. It’s built around four principles, thirteen guidelines, and a set of testable success criteria at Levels A, AA, and AAA. This post will walk you through what all of that actually means in plain terms.
In This Article
A Simple Example of How WCAG Works
What is WCAG?
WCAG stands for Web Content Accessibility Guidelines.
It is the internationally recognized set of standards for making websites, web apps, and digital content usable by people with disabilities. That includes people who use screen readers, navigate by keyboard instead of a mouse, rely on captions to understand audio, or use zoom and other assistive tools to browse the web.
Think of it less like a legal document and more like a shared checklist the industry has agreed on.
WCAG is the framework people use to check whether a website actually works for more people.
Imagine you opened a physical store. You’d want to make sure anyone could get through the door, read your signs, and find what they need, not just people who move and see in a specific way. WCAG is that same thinking, but applied to the web.
Who Creates WCAG?
WCAG is published by the World Wide Web Consortium (W3C), specifically through its Web Accessibility Initiative (WAI). W3C is the international body responsible for the core technical standards that shape how the web works (think of them as the rule-setters for the internet).
WCAG is used across web design, development, auditing, procurement, and policy work worldwide. When laws and regulations reference digital accessibility standards — in the U.S., the EU, Canada, and many other countries, WCAG is almost always what they point to.
Why WCAG Feels So Complicated
The official WCAG document is written first and foremost for accuracy, not for casual reading.
Every requirement needs to be specific enough that someone can objectively test against it. That’s why the language is so formal. W3C also publishes supporting Understanding documents and a Quick Reference tool to help explain what each part means in practice. Those are worth bookmarking once you’re ready to go deeper.
But here’s the part that trips people up….
You are probably asking: "Is my website accessible?" or "How do I make it more accessible?"
WCAG is written to answer a different question, "Which specific requirements does this page pass or fail?"
Both questions matter. They’re just approaching the same problem from different angles.
How WCAG Is Organized
WCAG is built in layers:
Principles → Guidelines → Success Criteria
Think of it like a filing cabinet. The Principles are the big drawers. The Guidelines are the folders inside each drawer. The Success Criteria are the individual documents in each folder (the actual checkpoints).
Principles
The four Principles (our drawers) are the foundation of everything in WCAG. All 86 success criteria in WCAG 2.2 fall under one of these
Perceivable
Operable
Understandable
Robust
Each one is broken down in more detail below.
Guidelines
Under those four Principles, WCAG includes 13 guidelines (our file folders). Each one describes a general goal, like "provide text alternatives for non-text content" or "make all functionality available from a keyboard."
Guidelines are useful for understanding the direction WCAG is headed, but they aren’t what you test against directly.
Success Criteria
Under each guideline, WCAG provides Success Criteria (the documents in our file folders that we need to take out and review). These are the specific pass-or-fail requirements that teams actually test against. They’re grouped into Level A, Level AA, and Level AAA.
The Principles explain the goal.
The Guidelines organize the goal.
The Success Criteria are the actual pass-or-fail checkpoints.
The Four WCAG Principles
Let’s break down the four principles.
Perceivable
People need to be able to notice and take in your content.
If someone can’t see an image, there should be text explaining what it shows. If someone can’t hear audio, there should be captions or a transcript. If your text doesn’t have enough contrast, many people will struggle to read it.
Perceivable means: nothing important should be invisible.
Example: An image of your team on your About page. If a screen reader user encounters it with no description, they’ll just hear "image" and move on. A short description like "The Acme Co. team at their 2024 company retreat" gives them the same context everyone else gets.
Operable
People need to be able to use your site and move through it.
That means your navigation and forms need to work with a keyboard alone (no mouse required), interactive elements need to be large enough to tap or click accurately, and users need enough time to complete tasks without content disappearing on them.
Operable means: your site should not require only one way of using it.
Example: A pop-up chat widget that can only be closed by clicking a tiny X in the corner. If someone is navigating by keyboard and can’t reach or activate that button, they’re stuck. That’s an operable failure.
Understandable
People need to be able to make sense of what they’re seeing and doing.
Your navigation should behave consistently across pages. Forms should tell people what’s needed before they submit, not just after. Error messages should explain what went wrong and how to fix it. Unexpected changes — like a page refreshing or a new window opening without warning — should not happen without notice.
Understandable means: people should not have to guess what is happening or what’s coming next.
Example: A checkout form that shows a red border around a field but doesn’t explain why. Someone who is color blind, or who has a cognitive disability, may not know what’s wrong or how to fix it. A message like "Please enter a valid email address" removes the guesswork.
Robust
Your content needs to work reliably across different browsers, devices, and assistive technologies — not just look fine in your own browser on your own laptop.
Robust is mostly about the code and structure behind your content. It needs to be built in a way that supports tools like screen readers, voice control software, and other assistive technologies that people depend on.
Robust means: your website should keep working as tools and technologies evolve.
Example: A custom dropdown menu built entirely with div elements and JavaScript instead of proper HTML. It might look great visually, but a screen reader may not recognize it as a menu at all — making it completely inaccessible to someone who is blind.
What the Guidelines Do
The Guidelines sit between the big-picture Principles and the specific Success Criteria. They answer questions like
What does it mean to make content perceivable?
What kinds of problems make a site hard to operate?
What helps users understand content and interactions?
For example, under the Perceivable principle, there are guidelines around text alternatives, time-based media (like video), adaptability, and color contrast. Under Operable, guidelines cover keyboard access, timing, seizure-safe content, navigation, and input methods. Under Understandable, they address readability, predictability, and helping users avoid errors. Under Robust, the focus is on compatibility with current and future tools.
You don’t need to memorize all 13 guidelines right now. For a first introduction, it’s enough to know that the guidelines are the main topic areas of accessibility concerns within each Principle.
What are Success Criteria
A Success Criterion is a specific, testable requirement under a guideline.
This is where WCAG gets specific. A success criterion might address whether images have text descriptions, whether a page can be navigated without a mouse, or whether error messages in a form are clearly identified. The language is intentionally precise because these are the items used for actual evaluation and conformance decisions.
So, when someone says
"Your site should meet WCAG 2.2 AA"
What they actually mean is
Your site should pass all Level A and Level AA success criteria that apply to your content.
What Levels A, AA, and AAA Mean
WCAG’s Success Criteria are grouped into three levels.
Level A
The starting floor. Level A covers the most critical barriers — things that can completely block someone from using your site at all. Every website should meet Level A. Skipping these is not a small oversight; it means some users may not be able to use your site at all.
Level AA
The standard most organizations aim for. Level AA includes all Level A requirements plus additional ones that make a meaningful difference for a much wider range of users. When laws and accessibility policies reference WCAG, Level AA is almost always the target they specify.
Level AAA
The highest bar. Level AAA includes all A, AA, and AAA criteria. W3C notes that it’s not realistic — or even expected — to meet every AAA criterion across an entire site. Some AAA requirements are specific to certain content types or contexts. That said, many AAA improvements are worth working toward where they make sense for your audience.
A is the starting floor.
AA is the common target.
AAA is the highest bar, but not usually the standard expectation across an entire site.
A Simple Example of How WCAG Works
Let’s say you have a contact form on your website. WCAG doesn’t just ass "Does the form exist?" It asks whether the form actually works for everyone who might need to use it.
Running that form through the lens of WCAG, you’d be asking things like
Can someone fill it out using only a keyboard?
Are the field labels clear about what's expected?
If someone misses a required field, does the error message tell them specifically what went wrong and how to fix it?
Is the text readable? Does the color contrast between the text and background meet the minimum ratio?
Can a screen reader user tell where they are as they move through the form?
That’s how WCAG works in practice. It turns vague ideas like "make it accessible" into concrete, checkable questions your team can actually act on.
What Beginners Should Focus On First
If WCAG is brand new to you, don’t start by trying to implement all the success criteria. That is a fast path to overwhelm.
Start here instead: can people perceive your content, use your navigation and forms, understand what’s happening, and rely on your site with different tools? Those four questions map directly to the four Principles, and they’re a solid anchor when you’re just getting started.
Once that foundation clicks, the Success Criteria become much more useful. They’re the detailed checklist you use to find and fix specific issues.
One more thing worth knowing early on: automated testing tools can help flag some accessibility problems, but they can’t catch everything. Manual review, human testing, and thoughtful design decisions are all part of the picture.
Final Takeaway
WCAG can look intimidating because the official standard is written for technical precision. But once you strip away the formal language, the structure is actually pretty logical.
WCAG is a framework for making web content more accessible. It’s organized into four Principles, thirteen Guidelines, and testable Success Criteria. Those criteria are grouped into Levels A, AA, and AAA, and they’re what determine whether content meets the standard.
Once the structure makes sense, the rest becomes much easier to learn — and the work of making your site more accessible becomes a lot less overwhelming.
We helps small businesses build websites that are accessible, clear, and easier for EVERYONE to use from the start. If you want a professional review of your site’s accessibility, we’d love to take a look.
WCAG FAQs
What does WCAG stand for?
WCAG stands for Web Content Accessibility Guidelines. It is the international standard, published by W3C, for making web content accessible.
What are the four principles of WCAG?
The four principles are Perceivable, Operable, Understandable, and Robust — often remembered by the acronym POUR.
What is the difference between guidelines and success criteria?
Guidelines are the broader topic areas or goals within each Principle. Success Criteria are the specific, testable requirements used to evaluate whether content meets the standard. The guidelines give you direction; the success criteria give you the actual checkpoints.
What WCAG level should most businesses aim for?
Level AA is the most widely referenced target and the one most accessibility laws and policies point to. It includes all Level A and Level AA Success Criteria.
Is WCAG only for developers?
Not at all. Developers work with it, but so do designers, content writers, marketers, business owners, and accessibility reviewers. WCAG covers content, visuals, forms, media, navigation, and user experience — not just code. If you have any role in how your website looks, reads, or functions, WCAG is relevant to you.
