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Compliance Guide
WCAG 2.1 Levels Explained: A-AA-AAA
What’s the difference between A, AA, and AAA compliance? We break down each level and help you pick the right target for your website.
Why WCAG Levels Matter
You’ve probably heard about WCAG compliance. Maybe you’ve even wondered what the letters actually mean. The truth is, it’s not complicated — but it does matter. A lot.
The Web Content Accessibility Guidelines (WCAG) set the standard for making websites work for everyone. That includes people using screen readers, keyboard navigation, or adjusting colors and text sizes. But here’s the thing: not every requirement has the same impact. Some are fundamental. Others are nice-to-have.
That’s where the levels come in. They’re like difficulty settings for accessibility. You’ve got A (basic), AA (stronger), and AAA (comprehensive). Each level builds on the one before it. And the level you target depends on your audience, your resources, and what you’re trying to achieve.
The Three Compliance Levels
Each level represents a growing set of requirements. You don’t skip levels — you build on them.
A
Level A
The foundation. Level A covers the essential accessibility features that every website should have. We’re talking about basic keyboard navigation, text alternatives for images, and consistent structure.
Alt text for images
Keyboard navigation
Form labels
Page structure
AA
Level AA
The standard. Most organizations aim for AA. It includes everything from Level A plus additional requirements around color contrast, focus indicators, and headings. This is what most accessibility regulations reference.
4.5:1 contrast ratio
Visible focus indicators
Proper heading hierarchy
All Level A requirements
AAA
Level AAA
The gold standard. Level AAA goes beyond what most websites need. It’s for specialized content like medical sites or government resources serving vulnerable populations. It requires even higher contrast, extended audio descriptions, and more.
7:1 contrast ratio
Extended descriptions
Sign language videos
All Level AA requirements
Choosing Your Target Level
Here’s the practical question: which level should you actually aim for?
If you’re running a public website, AA is the realistic target. Most Canadian accessibility laws reference AA compliance. It’s comprehensive enough to help the majority of users without requiring resources you probably don’t have.
Level A alone? It’s not enough. You’d be missing color contrast requirements, which means people with low vision won’t be able to read your content. You’d lack proper focus indicators, making keyboard navigation frustrating.
AAA is typically reserved for specific situations. If you’re designing a health resource, government site, or something serving people with cognitive disabilities, AAA shows real commitment. But it’s resource-intensive and honestly, not always necessary for commercial sites.
The key insight: don’t skip levels. You can’t claim AA compliance without meeting A first. Each level builds on the previous one. It’s a progression, not options you pick and choose from.
What Changes at Each Level
The practical differences you’ll actually implement
01
Moving from A to AA
The biggest jump is contrast. Level A doesn’t specify contrast requirements. Level AA demands 4.5:1 contrast for normal text. That means dark text on light backgrounds, or light text on dark ones — with actual numbers behind it. You’ll test your colors. You’ll probably redesign some buttons. You’ll add visible focus indicators so keyboard users see where they are. These aren’t small changes, but they’re manageable.
02
Moving from AA to AAA
Now contrast jumps to 7:1 — significantly darker and lighter. Your color palette might need rethinking. You’ll add extended descriptions for complex images. Videos need sign language interpretation. Captions aren’t enough anymore. Animated content needs pause controls. It’s comprehensive and it’s demanding. Most commercial websites stop at AA because the effort-to-benefit ratio shifts here.
Real-World Implementation
You don’t wake up one day and suddenly become AAA-compliant. It’s a journey. Most teams start by auditing their current site against Level A requirements. You’ll find missing alt text, forms without labels, and buttons that aren’t keyboard-accessible.
Then you work toward AA. This usually takes 2-6 months depending on site size. You’re testing colors, adding focus states, reviewing heading structure. Tools like WAVE, Axe DevTools, and NVDA (a free screen reader) become your friends.
AAA? That’s a longer conversation. You’d need dedicated resources. It’s not something you do as a side project. But here’s what matters: if you’re serious about accessibility, start with AA. Meet that standard. Then evaluate if AAA makes sense for your specific situation.
The good news: once you’re thinking about accessibility, the work compounds. Features you add for Level AA — better focus indicators, clearer headings, proper contrast — they help everyone. Not just people with disabilities.
Legal Context in Canada
What the law actually requires
In Canada, most accessibility requirements reference WCAG 2.1 Level AA. The Accessible Canada Act (ACA) sets expectations for public and large private organizations. Provincial laws in Ontario, Quebec, and British Columbia also reference AA compliance.
There’s no legal requirement for AAA. It’s genuinely optional. If you’re a public sector organization or large corporation, AA is the baseline. Smaller businesses have more flexibility, but the trend is moving toward AA as a standard practice.
This isn’t legal advice — you should consult with lawyers familiar with accessibility law in your jurisdiction. But the practical reality: if you’re targeting Canadian audiences, AA is the standard you’re measured against.
The Bottom Line
Level A is the foundation — but it’s not enough for a real commitment to accessibility.
Level AA is what you should target. It’s comprehensive, legally referenced, and achievable with proper planning.
Level AAA is the gold standard for specialized content, but it’s not the baseline for most organizations.
Start where you are. Audit your current site. Identify gaps. Work toward AA. You’ll build a better website for everyone — not just people with disabilities. That’s the real win.
Ready to improve your accessibility? Start by testing your contrast ratios and keyboard navigation. Both take an afternoon and they’ll show you exactly where to focus first.
Explore More GuidesImportant Disclaimer
This article provides educational information about WCAG 2.1 compliance levels. It’s not legal advice. Accessibility requirements vary by jurisdiction and organization type. Before implementing accessibility standards, consult with legal experts familiar with Canadian accessibility laws and your specific regulatory context. Requirements may differ based on your industry, organization size, and location.
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