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When people visit a website, they expect it to be usable regardless of their abilities. Yet many sites still contain barriers that prevent people with disabilities from engaging fully. The web accessibility guidelines developed by the World Wide Web Consortium (W3C) were created to address this problem. They provide a framework for building websites and apps that are accessible to all users, including those who rely on assistive technologies.
For organisations, accessibility is about more than compliance. It directly impacts customer experience, reputation, and in many cases, legal responsibility. The following guide explains what the web accessibility guidelines are, how they apply in practice, and why they should be central to digital projects today.
What are the Web Content Accessibility Guidelines?
WCAG refers to the Web Content Accessibility Guidelines, an international standard created by the World Wide Web Consortium (W3C) through its Web Accessibility Initiative. The guidelines explain how to make digital content usable for people with a wide range of disabilities, including visual, auditory, motor, and cognitive impairments.
Unlike broad policy statements, the guidelines are structured around testable criteria. Designers and developers can check whether a website or app meets the requirements and address any gaps. For this reason, WCAG is regarded as the foundation of modern web accessibility standards.
What is the Current Standard for Accessibility?
WCAG has evolved to keep pace with technology. The first version was released in 1999, followed by WCAG 2.0 in 2008 and WCAG 2.1 in 2018.
The latest WCAG guidelines are version 2.2, finalised in 2023. New success criteria were added to improve accessibility for people with cognitive impairments and those using mobile devices. One example is the requirement for clear focus indicators so users navigating with a keyboard can always see where they are on the page.
Work is already underway on WCAG 3.0, sometimes referred to as “Silver”. This future version is expected to provide a more flexible model of measuring accessibility, but widespread adoption is still some years away. For now, 2.2 is the current standard.
Learn why it’s important to prioritise WCAG 2.2 today instead of waiting for 3.0.
How Many WCAG Success Criteria Are There?
The guidelines are organised around success criteria that can be tested. These are grouped into three levels of conformance:
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Level A: Basic requirements that address the most significant barriers.
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Level AA: A broader set of requirements that represent the practical target for most organisations.
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Level AAA: The highest level, often suitable for specialised contexts but not always realistic for every website.
WCAG 2.1 contained 78 success criteria. Version 2.2 adds several more, increasing the emphasis on mobile accessibility and cognitive needs. Most organisations aim for Level AA conformance, as it balances practicality with inclusivity.
What Are the 4 Principles of WCAG?
The guidelines are built on four principles that define how accessible content should function.
Perceivable
Users must be able to perceive the content. For example, images should include text alternatives so that screen readers can describe them.
Operable
Interfaces need to be operable by different methods. A site should work with a keyboard as well as a mouse, and users should be given adequate time to complete tasks.
Understandable
Information and navigation should be clear and predictable. Consistent menus, descriptive form labels, and plain language all support this principle.
Robust
Content should remain accessible across different platforms and assistive technologies. Using semantic HTML helps ensure compatibility with tools such as screen readers.
These four principles of WCAG are the foundation on which all success criteria are built.
Find out more about these core principles in the UK Government’s guidance on web content accessibility.
Is WCAG a Legal Requirement in the UK?
In the UK, accessibility has legal as well as ethical importance. The Equality Act 2010 requires organisations to make reasonable adjustments so that people with disabilities are not placed at a disadvantage. Although the law does not specifically mention WCAG, the guidelines are widely recognised as the standard for online accessibility.
Government websites and apps must go further. The Public Sector Bodies (Websites and Mobile Applications) Accessibility Regulations 2018 require them to meet WCAG Level AA. Private sector organisations are also at risk if their websites or services exclude disabled users.
Courts are increasingly using WCAG compliance as the benchmark when accessibility disputes arise. The European Accessibility Act, which came into force in June 2025, has further shifted expectations. It requires digital products and services offered within EU member states to meet consistent accessibility standards. UK businesses that sell or operate in Europe must align with those requirements, adding another reason to follow the guidelines closely.
For UK organisations, WCAG compliance provides legal protection, supports international trade, and demonstrates a serious commitment to inclusion.
Does WCAG Apply to Mobile Apps?
The guidelines were originally written with websites in mind, but they apply equally to mobile apps. Apps have become a central part of daily life, and accessibility problems in this space can exclude large groups of users.
Consider an app that relies on swiping alone for navigation. For users with motor impairments, this can be impossible. The accessibility standards require that alternative navigation methods are available, such as buttons that provide the same functionality. Text scaling, colour contrast, and compatibility with screen readers also apply to mobile interfaces.
Organisations that design apps with accessibility in mind from the start not only avoid complaints but also deliver a smoother experience for all users.
Check out our guide on why mobile accessibility matters to learn more.
How to Check if a Website is WCAG Compliant
A website WCAG audit can reveal barriers that are invisible to the design team. Even if a site looks functional to its creators, it may still be inaccessible to many users.
Automated Tools
Tools such as WAVE or Axe can scan pages for obvious issues like missing alternative text or poor colour contrast. These are useful for identifying problems quickly, but they only cover a portion of the requirements.
Browse our guide to find out the limitations of solely relying on automated accessibility testing.
Manual Checks
Some aspects of accessibility require human review. Headings must be structured correctly, forms should be labelled clearly, and the site should follow a logical tab order. Automated tools cannot capture all of these details.
Testing with Assistive Technologies
Screen readers, voice recognition software, and alternative input devices can expose barriers that automated testing misses. For example, a form might have labels but still be confusing when read aloud.
Expert Audits
The most reliable approach is a professional audit that combines all of these methods. For example, in an accessibility review of Tesco’s checkout journey, missing form field labels meant screen reader users only heard “edit blank” instead of meaningful prompts.
Keyboard users also struggled because the basket could not be accessed through navigation or modal focus. These barriers would have prevented many customers from completing a purchase, showing how a single oversight can block an entire transaction.
How Do I Make My Website WCAG Compliant?
Begin with an Accessibility Audit
An audit highlights where a site fails to meet the guidelines. Prioritising the most critical barriers, such as inaccessible forms or poor navigation, helps create a clear action plan.
Apply Accessibility Principles in Design and Development
Design teams should choose colour palettes that meet contrast ratios, ensure layouts are responsive, and write content in clear language. Developers should use semantic code and ARIA attributes only where needed.
A financial services provider we worked with rebuilt its customer portal with accessibility at the centre. As a result, support calls dropped significantly because users with disabilities could complete transactions independently.
Test with Users
Involving people with disabilities in testing provides insights that technical reviews may miss. Their feedback ensures accessibility is not treated as a checklist but as a real measure of usability.
Want to put this into practice? Learn more in our How-to Guide for Inclusive User Testing.
Final Thoughts
These web accessibility standards underpin modern digital inclusion. Whether for websites or mobile apps, they set clear expectations that allow organisations to deliver inclusive digital experiences. The guidelines evolve with technology, and the latest WCAG guidelines reflect the growing importance of accessibility on mobile devices and for users with cognitive differences.
For organisations in the UK, WCAG compliance supports obligations under the Equality Act, aligns with regulations for public bodies, and reduces the risk of legal action. With the European Accessibility Act now in effect, it also helps businesses stay competitive in international markets.
Accessibility is not a one-off project but an ongoing responsibility. Regular audits, thoughtful design, and user testing keep digital services inclusive and effective.
Ready to make accessibility more than a one-off project? Find out how Arc Inclusion can help your organisation stay accessible and make inclusion part of every digital project.