Accessibility Checker: Audit WCAG Basics on Any Webpage
RankNibbler's accessibility checker scans any URL for the foundational WCAG issues — missing language attributes, absent skip-navigation links, incomplete ARIA landmarks, unlabelled form inputs, images without alt text, and empty links. Free, instant, no signup. Each issue flagged with specifics so you can fix fast.
What Is Web Accessibility?
Web accessibility means building websites that can be used by everyone, including people with disabilities who rely on assistive technologies like screen readers, keyboard-only navigation, switch devices, or speech recognition. The Web Content Accessibility Guidelines (WCAG) define the technical standards: WCAG 2.1 Level AA is the most commonly cited benchmark, and WCAG 2.2 expands on it with additional criteria for mobile and cognitive accessibility.
Accessibility is both a legal requirement in most developed countries (EU Accessibility Act, ADA in the US, Equality Act 2010 in the UK) and a large market issue — the CDC estimates 26% of US adults have some disability that can affect web use. A site that fails accessibility excludes a meaningful portion of its potential audience.
Why Accessibility Matters for SEO
Accessibility and SEO have significant overlap. Many of the signals Google uses to evaluate content quality also correlate with accessibility:
Semantic HTML
Screen readers and search engines both rely on semantic HTML to understand page structure. A <nav> tag tells both "this is navigation"; a <main> tag tells both "this is the primary content." Pages built with semantic HTML are easier to accessibility-audit and rank better.
Alt Text
Image alt attributes serve screen readers AND help Google understand what images are about. Missing alt text fails accessibility and blocks image SEO.
Descriptive Links
"Click here" links are bad for screen readers (they announce "link, click here" with no destination) AND bad for SEO (wasted anchor text signal). Descriptive anchor text fixes both.
Heading Structure
A logical H1-H6 hierarchy helps screen readers navigate AND helps Google understand content organisation. Flat or chaotic heading structures hurt both.
User Signals
Pages that fail accessibility produce worse user signals — higher bounce rates, shorter dwell times, lower engagement. Google uses these signals in ranking. Accessibility failures propagate into SEO failures indirectly.
What This Checker Audits
Language Attribute
The <html lang="en"> attribute tells screen readers which pronunciation model to use. Without it, screen readers may mispronounce content. Also helps Google serve the right language version in international SERPs.
Skip Navigation Link
A "skip to main content" link at the start of the page lets keyboard-only users bypass the navigation every time they load a page. Without it, they tab through every nav item on every page visit — exhausting.
ARIA Landmarks
Proper landmark elements (<header>, <nav>, <main>, <aside>, <footer>) let screen readers jump between sections. Pages using <div> everywhere force linear reading with no shortcuts.
Form Input Labels
Every <input>, <select>, and <textarea> needs a corresponding <label> (or an aria-label). Without it, screen reader users hear "edit field" with no idea what data to enter. Forms without labels are among the most common accessibility failures and directly block conversions.
Linked Image Alt Text
Images inside <a> tags must have alt text. Without it, the entire link is invisible to screen readers.
Empty Links
Anchor tags with no text, no aria-label, and no image alt text are unusable — the screen reader announces "link" with no destination information. See the dedicated empty links checker.
WCAG Levels Explained
| Level | Requirements | Typical Use |
|---|---|---|
| Level A | Minimum baseline; fixes the most critical issues | Legal minimum in some jurisdictions |
| Level AA | Covers all common barriers; the standard most laws reference | Recommended and legally required in most developed countries |
| Level AAA | Enhanced accessibility; not practical for all content | Government, healthcare, educational sites |
This checker targets Level AA basics. Full WCAG conformance requires deeper checks (colour contrast ratios, keyboard focus indicators, interactive widget ARIA, motion sensitivity, etc.) typically handled with dedicated accessibility audit tools.
Common Accessibility Quick Wins
- Add
lang="en"to the<html>element. - Add a skip-nav link as the first focusable element:
<a href="#main" class="skip">Skip to main content</a>. - Wrap content in semantic landmarks. Use
<header>,<nav>,<main>,<footer>appropriately. - Add labels to every form field. Visible
<label>is best;aria-labelworks for icon-only inputs. - Add alt text to every meaningful image. Decorative-only images can use
alt="". - Fix icon-only links with
aria-label. - Ensure sufficient colour contrast. 4.5:1 for normal text, 3:1 for large text.
- Never rely on colour alone to convey information. Use icons, text, or patterns alongside colour.
Related Accessibility & Quality Tools
- Image alt text checker — dedicated alt-text audit.
- Empty links checker — dedicated link text audit.
- Heading structure checker — validate H1-H6 hierarchy.
- Deprecated HTML checker — legacy tags often fail accessibility.
- Readability checker — cognitive accessibility.
- Site Audit — accessibility basics plus 30+ other checks.