Free Website Accessibility Checker

What website accessibility actually means

Website accessibility is the practice of building websites that work for everyone, including people who navigate the web differently than you might expect. About 1.3 billion people worldwide live with some form of disability. That includes people who are blind and use screen readers to hear web content read aloud, people with low vision who zoom in to 400% or use high-contrast modes, people with motor impairments who navigate entirely by keyboard or voice commands, and people with cognitive disabilities who rely on clear structure and plain language.

When a website is accessible, all of these users can read the content, fill out forms, make purchases, and interact with every feature the site offers. When it's not, they hit barriers: images they can't perceive because there's no text alternative, buttons they can't click because they only work with a mouse, forms they can't complete because the fields aren't labeled, or text they can't read because the contrast is too low.

The technical standard for measuring accessibility is WCAG, the Web Content Accessibility Guidelines. Published by the W3C (the same organization that maintains HTML and CSS standards), WCAG defines specific, testable criteria organized around four principles: content must be Perceivable, Operable, Understandable, and Robust. The current version most organizations target is WCAG 2.1 Level AA, which includes 50 success criteria covering everything from text alternatives for images to keyboard operability to error handling in forms.

Who needs to care about accessibility

The short answer is everyone with a public website. But some organizations face more immediate pressure than others.

Government agencies are legally required to meet accessibility standards under Section 508 (federal) and the DOJ's 2024 rule requiring WCAG 2.1 AA for state and local government sites. Deadlines fall in 2026 and 2027 depending on the size of the entity.

Businesses open to the public fall under ADA Title III. Courts have consistently ruled that websites count as places of public accommodation. Over 4,000 ADA web accessibility lawsuits are filed annually, and demand letters number in the tens of thousands.

Organizations receiving federal funding must comply with Section 504 of the Rehabilitation Act, which covers websites and digital content.

Companies doing business in the EU face the European Accessibility Act, which took effect in June 2025 and applies to a broad range of digital products and services.

Even if none of these categories apply directly to you, accessibility is increasingly a baseline expectation. Search engines favor accessible sites (proper heading structure, alt text, and semantic HTML all improve SEO). Users who encounter barriers don't file complaints; they leave and find a competitor who built their site properly.

The business case beyond legal risk

Legal compliance gets the most attention, but it's actually the least interesting reason to build accessible websites. The real business case is about reach and revenue.

People with disabilities represent a market of over $13 trillion in annual disposable income globally. In the US alone, the disability community controls approximately $490 billion in spending power. These aren't theoretical numbers. When your checkout flow doesn't work with a keyboard, you lose a sale. When your product images lack alt text, a blind customer can't tell what you're selling. When your videos don't have captions, you lose the 15% of the global population that has some degree of hearing loss.

There's also a significant overlap between accessibility and general usability. Fixing accessibility issues tends to make sites better for everyone. Clearer navigation helps mobile users. Better contrast helps anyone reading outdoors. Proper form labels reduce errors for all users, not just those using assistive technology. Captions help people watching videos in noisy environments or without headphones.

The Click-Away Pound Survey found that 69% of disabled consumers with access needs will click away from a website that presents barriers, taking an estimated $19.8 billion in revenue with them in the UK alone. The vast majority never contact the business to report the problem. They just leave.

How automated accessibility testing works

Automated accessibility checkers work by analyzing the HTML, CSS, and ARIA attributes of a web page against the rules defined in WCAG. The tool loads your page, inspects the DOM (the document structure the browser builds from your HTML), and checks each element against a set of known patterns that indicate accessibility violations.

For example, the tool checks every <img> element for an alt attribute. If the image is decorative, alt="" is correct. If it conveys information, the alt text should describe what the image shows. A missing alt attribute entirely is always a violation because the screen reader has no way to communicate the image to the user.

Similarly, the tool evaluates every text element's contrast ratio against its background color. WCAG 2.1 AA requires a minimum contrast ratio of 4.5:1 for normal text and 3:1 for large text (defined as 18pt regular or 14pt bold). The tool calculates these ratios mathematically and flags any element that falls below the threshold.

Other checks include verifying that form inputs have associated labels (either through a <label> element or aria-label), that the page has a valid heading hierarchy (no skipping from h1 to h4), that interactive elements are keyboard-focusable, and that the page specifies its language for screen reader pronunciation.

What automated testing catches (and what it misses)

Automated tools reliably catch about 30 to 40% of WCAG 2.1 Level AA success criteria. That sounds low, but those criteria cover the most common and highest-impact issues. Missing alt text, contrast failures, empty form labels, missing page language, empty links, and empty buttons account for the overwhelming majority of errors found on most websites.

What automated tools can't evaluate are things that require human judgment. Is the alt text actually meaningful, or did someone write "image" for every photo? Does the tab order make logical sense? Can a user understand the purpose of a link from its text alone? Are custom JavaScript widgets (accordions, carousels, modal dialogs) properly communicating their state to assistive technology? These require manual testing to assess properly.

The practical approach is to use automated scanning as your first line of defense. Fix everything the scanner finds, then do targeted manual testing for the things automation can't cover. This gets you to a solid baseline at minimal cost, and you can layer on more thorough manual audits as your accessibility practice matures.

Common accessibility issues and how to fix them

The WebAIM Million study analyzes the home pages of the top one million websites every year. The results are consistent, and honestly a bit depressing: 95.9% of home pages have detectable WCAG failures. Here are the issues that show up most often and what to do about them.

Low contrast text

Found on 83% of home pages. This is the single most common accessibility issue on the web. Light gray text on a white background might look sleek in a design mockup, but it creates a real barrier for people with low vision, color blindness, or anyone reading on a screen in bright sunlight. The fix is straightforward: adjust your text or background colors to meet the 4.5:1 contrast ratio. There are free contrast checker tools that calculate the ratio for any color pair.

Missing image alt text

Found on 68% of home pages. When a screen reader encounters an image without alt text, it either skips it entirely or reads the file name, which is usually something unhelpful like "IMG_4382.jpg" or "hero-banner-v3-final.png". Every informational image needs a concise description of what it shows. Decorative images (visual flourishes that don't convey meaning) should have an empty alt attribute (alt="") so screen readers know to skip them.

Missing form input labels

Found on 56% of home pages. When a form field doesn't have a programmatically associated label, a screen reader user hears something like "edit text" with no indication of what they're supposed to type. Every input needs a label, either a visible <label> element linked via the for attribute, or an aria-label for cases where a visible label doesn't fit the design. Placeholder text alone is not a substitute because it disappears when the user starts typing.

Empty links and buttons

Found on over 40% of home pages combined. An icon button with no accessible name is meaningless to a screen reader. A link that wraps an image but has no text alternative results in the screen reader announcing just "link" with no indication of where it goes. Every interactive element needs a text label that describes its purpose, whether through visible text, alt text on a contained image, or an aria-label attribute.

Missing page language

Found on 18% of home pages. The lang attribute on the <html> element tells screen readers which language to use for pronunciation. Without it, a screen reader might try to read French content with English pronunciation rules, making it incomprehensible. This is a one-line fix: <html lang="en"> (or whatever language your content is in).

Broken heading structure

Screen reader users navigate by headings the way sighted users scan a page visually. When headings skip levels (jumping from h1 to h4) or are used for styling rather than structure (making something an h3 because the font size looks right), the page becomes harder to navigate. Use headings in order to create a logical outline of your content, and use CSS for visual styling rather than heading levels.

Frequently asked questions

Related tools: Home · ADA compliance checker · WCAG compliance checker · ADA website compliance · Accessibility audit · ADA compliance for ecommerce · ADA compliance for small business

What website accessibility actually means

Website accessibility is the practice of building websites that work for everyone, including people who navigate the web differently than you might expect. About 1.3 billion people worldwide live with some form of disability. That includes people who are blind and use screen readers to hear web content read aloud, people with low vision who zoom in to 400% or use high-contrast modes, people with motor impairments who navigate entirely by keyboard or voice commands, and people with cognitive disabilities who rely on clear structure and plain language.

When a website is accessible, all of these users can read the content, fill out forms, make purchases, and interact with every feature the site offers. When it's not, they hit barriers: images they can't perceive because there's no text alternative, buttons they can't click because they only work with a mouse, forms they can't complete because the fields aren't labeled, or text they can't read because the contrast is too low.

The technical standard for measuring accessibility is WCAG, the Web Content Accessibility Guidelines. Published by the W3C (the same organization that maintains HTML and CSS standards), WCAG defines specific, testable criteria organized around four principles: content must be Perceivable, Operable, Understandable, and Robust. The current version most organizations target is WCAG 2.1 Level AA, which includes 50 success criteria covering everything from text alternatives for images to keyboard operability to error handling in forms.

Who needs to care about accessibility

The short answer is everyone with a public website. But some organizations face more immediate pressure than others.

Government agencies are legally required to meet accessibility standards under Section 508 (federal) and the DOJ's 2024 rule requiring WCAG 2.1 AA for state and local government sites. Deadlines fall in 2026 and 2027 depending on the size of the entity.

Businesses open to the public fall under ADA Title III. Courts have consistently ruled that websites count as places of public accommodation. Over 4,000 ADA web accessibility lawsuits are filed annually, and demand letters number in the tens of thousands.

Organizations receiving federal funding must comply with Section 504 of the Rehabilitation Act, which covers websites and digital content.

Companies doing business in the EU face the European Accessibility Act, which took effect in June 2025 and applies to a broad range of digital products and services.

Even if none of these categories apply directly to you, accessibility is increasingly a baseline expectation. Search engines favor accessible sites (proper heading structure, alt text, and semantic HTML all improve SEO). Users who encounter barriers don't file complaints; they leave and find a competitor who built their site properly.

The business case beyond legal risk

Legal compliance gets the most attention, but it's actually the least interesting reason to build accessible websites. The real business case is about reach and revenue.

People with disabilities represent a market of over $13 trillion in annual disposable income globally. In the US alone, the disability community controls approximately $490 billion in spending power. These aren't theoretical numbers. When your checkout flow doesn't work with a keyboard, you lose a sale. When your product images lack alt text, a blind customer can't tell what you're selling. When your videos don't have captions, you lose the 15% of the global population that has some degree of hearing loss.

There's also a significant overlap between accessibility and general usability. Fixing accessibility issues tends to make sites better for everyone. Clearer navigation helps mobile users. Better contrast helps anyone reading outdoors. Proper form labels reduce errors for all users, not just those using assistive technology. Captions help people watching videos in noisy environments or without headphones.

The Click-Away Pound Survey found that 69% of disabled consumers with access needs will click away from a website that presents barriers, taking an estimated $19.8 billion in revenue with them in the UK alone. The vast majority never contact the business to report the problem. They just leave.

How automated accessibility testing works

Automated accessibility checkers work by analyzing the HTML, CSS, and ARIA attributes of a web page against the rules defined in WCAG. The tool loads your page, inspects the DOM (the document structure the browser builds from your HTML), and checks each element against a set of known patterns that indicate accessibility violations.

For example, the tool checks every <img> element for an alt attribute. If the image is decorative, alt="" is correct. If it conveys information, the alt text should describe what the image shows. A missing alt attribute entirely is always a violation because the screen reader has no way to communicate the image to the user.

Similarly, the tool evaluates every text element's contrast ratio against its background color. WCAG 2.1 AA requires a minimum contrast ratio of 4.5:1 for normal text and 3:1 for large text (defined as 18pt regular or 14pt bold). The tool calculates these ratios mathematically and flags any element that falls below the threshold.

Other checks include verifying that form inputs have associated labels (either through a <label> element or aria-label), that the page has a valid heading hierarchy (no skipping from h1 to h4), that interactive elements are keyboard-focusable, and that the page specifies its language for screen reader pronunciation.

What automated testing catches (and what it misses)

Automated tools reliably catch about 30 to 40% of WCAG 2.1 Level AA success criteria. That sounds low, but those criteria cover the most common and highest-impact issues. Missing alt text, contrast failures, empty form labels, missing page language, empty links, and empty buttons account for the overwhelming majority of errors found on most websites.

What automated tools can't evaluate are things that require human judgment. Is the alt text actually meaningful, or did someone write "image" for every photo? Does the tab order make logical sense? Can a user understand the purpose of a link from its text alone? Are custom JavaScript widgets (accordions, carousels, modal dialogs) properly communicating their state to assistive technology? These require manual testing to assess properly.

The practical approach is to use automated scanning as your first line of defense. Fix everything the scanner finds, then do targeted manual testing for the things automation can't cover. This gets you to a solid baseline at minimal cost, and you can layer on more thorough manual audits as your accessibility practice matures.

Common accessibility issues and how to fix them

The WebAIM Million study analyzes the home pages of the top one million websites every year. The results are consistent, and honestly a bit depressing: 95.9% of home pages have detectable WCAG failures. Here are the issues that show up most often and what to do about them.

Low contrast text

Found on 83% of home pages. This is the single most common accessibility issue on the web. Light gray text on a white background might look sleek in a design mockup, but it creates a real barrier for people with low vision, color blindness, or anyone reading on a screen in bright sunlight. The fix is straightforward: adjust your text or background colors to meet the 4.5:1 contrast ratio. There are free contrast checker tools that calculate the ratio for any color pair.

Missing image alt text

Found on 68% of home pages. When a screen reader encounters an image without alt text, it either skips it entirely or reads the file name, which is usually something unhelpful like "IMG_4382.jpg" or "hero-banner-v3-final.png". Every informational image needs a concise description of what it shows. Decorative images (visual flourishes that don't convey meaning) should have an empty alt attribute (alt="") so screen readers know to skip them.

Missing form input labels

Found on 56% of home pages. When a form field doesn't have a programmatically associated label, a screen reader user hears something like "edit text" with no indication of what they're supposed to type. Every input needs a label, either a visible <label> element linked via the for attribute, or an aria-label for cases where a visible label doesn't fit the design. Placeholder text alone is not a substitute because it disappears when the user starts typing.

Empty links and buttons

Found on over 40% of home pages combined. An icon button with no accessible name is meaningless to a screen reader. A link that wraps an image but has no text alternative results in the screen reader announcing just "link" with no indication of where it goes. Every interactive element needs a text label that describes its purpose, whether through visible text, alt text on a contained image, or an aria-label attribute.

Missing page language

Found on 18% of home pages. The lang attribute on the <html> element tells screen readers which language to use for pronunciation. Without it, a screen reader might try to read French content with English pronunciation rules, making it incomprehensible. This is a one-line fix: <html lang="en"> (or whatever language your content is in).

Broken heading structure

Screen reader users navigate by headings the way sighted users scan a page visually. When headings skip levels (jumping from h1 to h4) or are used for styling rather than structure (making something an h3 because the font size looks right), the page becomes harder to navigate. Use headings in order to create a logical outline of your content, and use CSS for visual styling rather than heading levels.

Frequently asked questions

Related tools: Home · ADA compliance checker · WCAG compliance checker · ADA website compliance · Accessibility audit · ADA compliance for ecommerce · ADA compliance for small business