Cover image for Web Accessibility and Usability: Designing for All Users

Introduction: Why Designing for All Users Matters

Websites serve as the primary gateway to information, services, and opportunities. Yet 94.8% of the world's top one million homepages fail basic accessibility standards, effectively locking out the 1.3 billion people globally who experience significant disabilities—that's 16% of the population.

The most common barrier isn't a technical edge case. Low contrast text appears on 79.1% of homepages, making content unreadable for users with visual impairments and difficult for everyone in bright sunlight.

The problem extends beyond people with permanent disabilities. Accessible design benefits users with temporary limitations (a broken arm, lost glasses), situational constraints (noisy environments, slow internet), and aging populations experiencing declining vision and motor control.

When we design for accessibility, we're not creating a separate experience for a minority—we're improving usability for everyone.

For climate tech and sustainability organizations, this represents a critical misalignment between mission and practice. Companies working to create an equitable, sustainable future cannot afford to exclude users from their digital presence.

Accessibility and usability aren't separate concerns but interconnected pillars of inclusive design that expand reach, strengthen brand reputation, and demonstrate authentic commitment to equity.

TLDR: Key Takeaways

  • Accessible design removes barriers for people with disabilities while improving usability for everyone
  • WCAG 2.1 Level AA standards address most accessibility needs and legal requirements
  • The disability market represents 1.3 billion people with $13 trillion in global purchasing power
  • Accessible sites receive 23% more organic traffic and rank 12% higher than inaccessible competitors
  • Proactive accessibility costs 60% less than retrofitting and helps avoid the 5,000+ lawsuits filed annually

Understanding Accessibility and Usability: Definitions and Distinctions

What is Web Accessibility?

Web accessibility ensures that people with disabilities can perceive, understand, navigate, and interact with digital products equally. This includes designing for diverse disabilities:

  • Visual impairments: Blindness, low vision, and color vision deficiencies (affecting 8% of males and 0.5% of females of Northern European descent)
  • Auditory disabilities: Deafness and hearing loss requiring captions and transcripts
  • Motor limitations: Physical conditions affecting mouse or keyboard use, such as tremors or limited dexterity
  • Cognitive and neurological conditions: Affecting learning, memory, attention, and information processing

Accessibility features also serve users without permanent disabilities. Someone with a broken arm experiences temporary motor limitations, while a person using a phone in bright sunlight faces situational visual constraints.

Slow internet connections create technical barriers. Accessible design accommodates the full spectrum of human diversity and circumstances.

Infographic

How Usability Differs

Usability measures how effectively, efficiently, and satisfactorily users can achieve their goals with a product. According to ISO 9241-11:2018, usability focuses on the user experience for all users, emphasizing:

  • Intuitive navigation that helps users find information quickly
  • Clear information architecture that organizes content logically
  • Streamlined task flows that minimize steps and cognitive load
  • Effective visual design that guides attention and communicates hierarchy

Usability research improves the overall user experience, but it often doesn't specifically address disability-related needs. That's where accessibility becomes essential.

Key Differences Between the Two

The primary distinction lies in focus and scope:

Accessibility addresses discriminatory barriers that prevent people with disabilities from using digital products. It often involves technical requirements like proper code structure for screen readers, sufficient color contrast ratios, and keyboard navigation support.

Accessibility also carries legal weight through standards like the Americans with Disabilities Act (ADA) and Web Content Accessibility Guidelines (WCAG).

Usability addresses effectiveness and satisfaction for all users, focusing more on visual design, user flow optimization, and task completion efficiency. It's primarily a competitive and customer satisfaction concern rather than a compliance requirement.

Why Both Matter for Inclusive Design

Inclusive design means designing for the full range of human diversity in ability, language, culture, gender, age, and other forms of difference. Neither accessibility nor usability alone creates truly inclusive experiences—both are essential.

The evidence supports this integrated approach. Enhancing cognitive accessibility features increases cognitive engagement for individuals without disabilities, not just those with cognitive impairments.

When we design inclusively from the start, we create digital products that serve the widest possible audience while avoiding the higher costs of retrofitting accessibility later.

Infographic

The Intersection: Where Accessibility Meets Usability

The Curb-Cut Effect in Digital Design

The "curb-cut effect" describes how features designed for disability access benefit everyone. Curb cuts were required for wheelchair users but now help parents with strollers, travelers with luggage, and delivery workers with carts. Digital accessibility creates similar universal benefits.

Examples of Overlapping Benefits

Captions and transcripts help people who are deaf or hard of hearing. They also benefit:

  • People in noisy environments who can't hear audio
  • Non-native speakers learning vocabulary and pronunciation
  • Users in quiet spaces where audio would disturb others
  • Anyone who prefers reading to listening or wants to search video content

People with motor disabilities rely on keyboard navigation to navigate without a mouse. Power users benefit too:

  • Keyboard shortcuts boost efficiency for repetitive tasks
  • Broken or malfunctioning pointing devices become non-issues
  • Eating lunch or holding a child doesn't interrupt work

Sufficient color contrast (minimum 4.5:1 ratio) helps people with low vision and color blindness. It equally benefits:

  • Everyone using devices in bright sunlight or poorly lit spaces
  • Older users experiencing natural vision decline
  • Anyone viewing content on low-quality displays

Cognitive disabilities and learning differences require clear, simple language. But everyone gains:

  • Non-native speakers grasp content more easily
  • Experts from other fields access specialized information faster
  • Time-pressed readers scan and comprehend quickly

The "Usable Accessibility" Approach

These overlapping benefits only work when accessibility features are genuinely usable, not just technically compliant.

Meeting technical accessibility standards isn't enough. Features must be implemented in ways that actually work for users. Automated testing tools catch only about 30% of accessibility issues because they can't evaluate subjective quality.

Consider alt text for images. A screen reader can detect that an alt attribute exists (technically compliant), but if the text reads "image123.jpg" instead of describing the image's content and purpose, it provides no value to users.

True accessibility requires understanding user needs and testing with people who use assistive technologies.

Infographic

When to Prioritize One Over the Other

Accessibility must take precedence when:

  • Legal compliance is required (government contracts, public services)
  • Serving users with known disabilities in your audience
  • Addressing barriers that completely block access to content or functionality

Addressing both together from the start is more efficient than adding accessibility later. While some requirements may initially seem to conflict with aesthetic preferences, creative solutions almost always exist.

For climate tech companies building digital products, integrating accessibility from day one ensures solutions remain both beautiful and inclusive—reaching the widest possible audience for environmental impact.

Common Barriers and How to Address Them

Visual Barriers

The problem: Low contrast text affects 79.1% of homepages, making content unreadable for users with visual impairments and difficult for everyone in challenging lighting conditions. Other issues include using color as the only way to convey information and missing text alternatives for images.

Solutions:

  • Ensure minimum 4.5:1 contrast ratio for normal text and 3:1 for large text (WCAG Level AA)
  • Use text labels alongside color coding (not "click the red button" but "click the Submit button")
  • Write descriptive alt text that conveys both content and purpose ("graph showing 40% increase in sales from Q1 to Q2" not "graph")
  • Test designs with color blindness simulators

Auditory Barriers

Video content without captions excludes people who are deaf or hard of hearing, while audio-only information with no visual alternative creates similar barriers.

Solutions:

  • Add synchronized captions to all video content (not just auto-generated captions, which average 70-80% accuracy)
  • Provide transcripts for podcasts and audio content
  • Ensure visual indicators accompany audio alerts (a visible notification when a form error occurs, not just a beep)
  • Include visual cues for important audio information in videos

Motor/Physical Barriers

Mouse-only navigation blocks users who can't use pointing devices, while small click targets frustrate users with tremors or limited dexterity.

Time-limited interactions pressure users who need more time to complete tasks.

Solutions:

  • Ensure full keyboard accessibility (users can navigate and interact using Tab, Enter, and arrow keys)
  • Make buttons and links at least 44×44 CSS pixels (WCAG 2.1 Level AAA) or 24×24 pixels minimum (WCAG 2.2 Level AA)
  • Avoid time limits or allow users to extend them before expiration
  • Provide large, clearly separated click targets with sufficient spacing

Cognitive Barriers

Complex navigation confuses users trying to find information, while unclear instructions leave users uncertain how to complete tasks.

Inconsistent design patterns force users to relearn interfaces on each page, and information overload overwhelms users with too many choices or dense content.

Solutions:

  • Use clear headings (H1, H2, H3) and logical structure to organize content
  • Provide clear error messages that explain what went wrong and how to fix it
  • Maintain consistent navigation, terminology, and design patterns throughout the site
  • Break complex tasks into smaller steps with progress indicators
  • Use white space and visual hierarchy to reduce cognitive load

Technical Implementation Barriers

Missing form labels affect 48.2% of homepages, making forms unusable with screen readers.

Improper heading hierarchy confuses navigation, while inaccessible custom widgets lack keyboard support and screen reader compatibility.

Solutions:

  • Use semantic HTML elements (<nav>, <main>, <header>, <button>) instead of generic <div> tags
  • Ensure proper heading structure (don't skip from H1 to H3)
  • Label all form fields with associated <label> elements, not just placeholder text
  • Add ARIA labels to custom widgets when semantic HTML isn't sufficient
  • Test with actual screen readers (NVDA, JAWS, VoiceOver) to verify functionality

Testing for Barriers

Once you've addressed common barriers, testing ensures your solutions work in practice. Effective accessibility testing requires multiple approaches:

Testing methods to combine:

  • Automated testing catches syntax errors quickly but identifies only 30% of WCAG issues—tools like WAVE, axe-core, and Lighthouse flag missing alt text, contrast failures, and improper markup
  • Manual testing evaluates subjective quality that automation can't assess, including whether alt text is descriptive, headings are logical, and content makes sense (catches an additional 40% of issues)
  • User testing with people who have disabilities reveals real-world usability problems that other methods miss, as the remaining 30% of issues only surface when actual users navigate with screen readers, keyboard-only input, or other assistive technologies

Implementing Accessible and Usable Design: A Practical Framework

Infographic

Following Established Standards

Web Content Accessibility Guidelines (WCAG) 2.1 provides the internationally recognized standard with three conformance levels:

  • Level A: Minimum accessibility, addressing the most severe barriers
  • Level AA: The target for most legislation and the practical standard for compliance
  • Level AAA: The highest level, not recommended as a blanket policy because it's impossible to satisfy all AAA criteria for some content types

WCAG AA satisfies most legal requirements globally:

Building an Accessible Design Process

Shift left by building accessibility into the design process from the start rather than fixing it later:

  1. Include accessibility in design briefs - Specify WCAG Level AA compliance alongside project goals
  2. Use accessible design systems - Start with component libraries featuring built-in accessibility
  3. Conduct accessibility reviews at each stage - Check wireframes, designs, and prototypes before development
  4. Foster cross-functional collaboration - Accessibility spans design, development, and content creation
  5. Establish accessibility champions - Assign team members to maintain expertise and advocate for inclusion

Tools and Resources

Testing your designs requires the right combination of automated and manual tools:

Automated testing:

Learning resources:

  • W3C Web Accessibility Initiative (WAI) guidelines and tutorials
  • WebAIM articles and training materials
  • Accessible design systems like the U.S. Web Design System

User testing with real people:

Automated tools catch only about 57% of accessibility issues. Involve people with disabilities in testing sessions to validate that technically compliant features work in real-world scenarios.

The Business Case: Why Accessible Design Drives Results

Expanding Your Addressable Market

The disability market represents massive purchasing power often overlooked by businesses. The WHO estimates 1.3 billion people—16% of the global population—experience significant disability.

In the US, people with disabilities control over $490 billion in disposable income. Globally, the "Purple Pound" in the UK is valued at £274 billion in spending power from disabled households.

This market extends beyond people with permanent disabilities. Accessible design also serves aging populations, people with temporary injuries, and anyone facing situational limitations.

Every design decision that removes barriers expands your potential audience.

SEO and Technical Benefits

Accessible design creates tangible technical advantages. Many accessibility practices directly improve search engine optimization:

  • Proper heading structure helps search engines understand content hierarchy
  • Descriptive alt text provides context for images
  • Clear page titles improve search result relevance
  • Semantic HTML signals content meaning to crawlers

A 2025 study of 10,000 websites found that accessible sites received approximately 23% more organic traffic than less accessible competitors. Accessible sites also rank 12% higher on average because search engines reward well-structured, semantic content.

Accessible sites also demonstrate better user engagement:

  • Cart abandonment: 23% on accessible sites vs. 69% on inaccessible ones
  • Higher conversion rates across all user segments
  • Improved session duration and page engagement

These metrics reflect the direct impact on revenue and business outcomes.

Infographic

Legal Protection and Risk Mitigation

Digital accessibility litigation is accelerating rapidly. More than 5,000 lawsuits were filed in 2025, representing a 20% surge over 2024. E-commerce bears the brunt, accounting for nearly 70% of all ADA web lawsuits.

Notably, 22.6% of lawsuits in the first half of 2025 targeted websites with accessibility widgets or overlays installed, dispelling the myth that automated "quick fix" tools provide legal protection.

Proactive accessibility built into design and development is far less expensive than reactive fixes or legal settlements.

Brand Reputation and Values Alignment

Commitment to accessibility demonstrates values of inclusion and equity. For purpose-driven organizations in climate tech and sustainability sectors, this alignment is particularly important. Companies working to create an equitable, sustainable future must ensure their digital presence reflects those inclusive values.

Environmental and social equity are inseparable goals. We help climate-focused companies align their digital presence with their inclusive mission through strategic accessible design that reflects these values.

Frequently Asked Questions

What are usability and accessibility in web design?

Usability measures how effectively users achieve their goals, while accessibility ensures people with disabilities can perceive, navigate, and interact with digital products. Together, they create inclusive experiences for all users.

Why are usability and accessibility important in web design?

They expand your market to 1.3 billion people with disabilities, reduce legal risk from 5,000+ annual lawsuits, and improve engagement for all users. Accessible sites also receive 23% more organic traffic.

How much does it cost to make a website accessible?

Comprehensive accessibility audits range from $10,000 to $30,000 depending on complexity. Building accessibility from the start adds 10-20% to development costs, while retrofitting later costs significantly more.

What are the most common accessibility mistakes designers make?

Top failures include low contrast text (79.1% of sites), missing alt text (55.5%), missing form labels (48.2%), and empty links or buttons. These basic issues block millions but are straightforward to fix.

Do I need to test with real users who have disabilities?

Yes. Automated tools catch only 30% of accessibility issues, and real-world usability problems only surface when actual users navigate with assistive technologies. Testing with disabled users is essential.

Can a website be accessible and still look beautiful?

Absolutely. Color contrast, clear typography, and logical layouts enhance visual design rather than constrain it. Many award-winning websites demonstrate that accessible design can be stunning.