Accessibility and SEO: Technical Checks That Help Users and Search Engines

Accessibility and SEO: where the overlap is real

Accessible websites remove barriers for people with disabilities. Search engine optimisation helps search engines discover, understand and present pages to searchers. Some technical practices support both goals because they make page meaning, navigation or media easier to interpret. Others are vital for accessibility but should not be sold as ranking tactics.

That distinction matters. Google advises site owners to focus on people-first content and an overall good page experience, while also stating that E-E-A-T itself is not a specific ranking factor. The safer approach is therefore to fix accessibility barriers because they affect real users, and to recognise SEO benefits only where search documentation supports the connection. See Google's people-first content guidance.

For accessibility, the current W3C recommendation is WCAG 2.2. WCAG is a technical standard; legal obligations vary by jurisdiction, organisation and service. Meeting a checklist in this article should not be treated as a legal-compliance opinion. W3C maintains a separate overview of accessibility laws and policies for that reason.

What helps both accessibility and SEO — and what does not

Use the table below to decide why you are fixing an issue. The final column deliberately separates documented search overlap from accessibility work that should stand on its own merits.

Foundation checks: keyboard access, focus and contrast

Start with barriers that can stop someone using the page at all. These are not optional “SEO enhancements”; they are core accessibility checks.

1. Test the complete task with a keyboard

Use Tab, Shift + Tab, arrow keys where appropriate, Enter, Space and Escape to operate navigation, menus, forms, dialogs and other controls. WCAG 2.2 requires functionality to be operable through a keyboard interface where the criterion applies, and users must not become trapped in a component. W3C's keyboard-control guidance explains the objective.

Do not stop at “I can tab through the page.” Check that the focus order makes sense, every interactive element can actually be activated, menus can be exited, and no custom widget requires a mouse-only gesture.

2. Make keyboard focus visible

A sighted keyboard user needs to know which control currently has focus. WCAG 2.2 Success Criterion 2.4.7 requires a visible keyboard-focus indicator at Level AA. Removing browser outlines without supplying an equally clear replacement can therefore create a real barrier. See W3C's Focus Visible explanation.

3. Check contrast with the right thresholds

For WCAG 2.2 Level AA, normal text generally needs a contrast ratio of at least 4.5:1 against its background; large-scale text has a 3:1 minimum. Meaningful user-interface components and graphical objects are covered separately by the 3:1 non-text contrast requirement. W3C documents the text contrast requirement and non-text contrast requirement separately.

Contrast is a good example of why the accessibility/SEO distinction matters: poor contrast can make a page unusable for some people, but there is no reason to tell stakeholders that hitting 4.5:1 is itself an SEO ranking threshold.

Alt text and semantic HTML: strong overlap, easy to get wrong

Write alt text for the image's purpose

The old rule “every image needs descriptive alt text” is too blunt. Informative images need a text alternative that conveys their purpose in context. Decorative or redundant images should normally use an empty attribute, alt="", so screen readers can ignore them. W3C's alt-text decision tree is a useful way to decide which treatment applies.

This is also one of the clearest SEO overlaps. Google's image guidance says it uses alt text, together with page content and image-understanding systems, to understand an image's subject matter. That does not justify keyword stuffing: Google explicitly recommends useful, contextual descriptions. See Google's image SEO guidance.

For example:

<!-- Informative image: describe the useful meaning -->
<img src="/images/product-discount.jpg" alt="Red product box with a 20% discount label">

<!-- Decorative image: keep the alt attribute, but leave it empty -->
<img src="/images/decorative-wave.svg" alt="">

Use HTML that communicates structure and purpose

Meaningful elements such as headings, paragraphs, lists, navigation regions, buttons and labelled form controls give browsers and assistive technologies useful structure. W3C notes that well-structured pages support navigation and can also help search engines index content. Its page-structure tutorial is a good implementation reference.

Do not treat semantic HTML as a licence to add unnecessary ARIA or wrapper elements. The goal is to represent what the interface actually is, not to make the source look more “optimised”.

Headings, page titles and links: make the page understandable before optimising it

Use headings to describe real sections

Headings should reflect the content hierarchy and let a reader scan the page. W3C recommends nesting headings by rank and notes that skipping ranks can be confusing and should be avoided where possible. That is more accurate than claiming that an H3 directly after an H1 automatically “breaks” SEO or WCAG. Read W3C's heading guidance.

For a deeper ScanMySEO explanation of page hierarchy, see the headings best-practice guide.

Give each page a descriptive title

WCAG 2.2 Success Criterion 2.4.2 requires web pages to have titles that describe their topic or purpose. This also aligns closely with search: Google recommends descriptive, concise <title> text and may use the title element, the main visual title and heading elements when generating a search-result title link. Compare W3C's Page Titled guidance with Google's title-link guidance.

Use links that have a destination and explain it

Descriptive link text is useful to people navigating normally, people reviewing a list of links with assistive technology, and search engines. Google recommends standard crawlable <a href="..."> links and says good anchor text should be descriptive, reasonably concise and relevant to the destination. W3C likewise requires link purpose to be determinable from the link text or its programmatic context.

Avoid vague repeated links such as “click here” when a destination can be named directly. Also avoid building essential navigation from clickable <div> or <span> elements when a real link or button is the correct control. Google's link best practices explain what its crawlers can reliably extract.

Forms and controls: test whether a user can understand the task

A form can be technically present in the DOM and still be difficult or impossible to complete. Every control needs an understandable purpose, and visible labels are usually the clearest solution for text inputs, checkboxes, radio buttons and selects. W3C's form-label guidance recommends explicitly associating labels and controls where possible.

Check more than labels:

• Required fields and expected formats are explained before the user makes an error.
• Error messages identify the affected field and explain how to fix the problem.
• Icon-only controls have an accessible name that matches their purpose.
• Placeholder text is not the only instruction or label.
• Validation feedback can be perceived by users who are not looking directly at the affected field.

These improvements may reduce task friction and failed submissions, but that practical benefit should not be rewritten as an unsupported claim that labelled forms “increase rankings”.

Accessibility is not an E-E-A-T shortcut

Do not document accessibility fixes as “proof of E-E-A-T” or as an authority signal sent to Google. Google's own guidance says E-E-A-T is not a specific ranking factor. Accessibility work can contribute to a better, more trustworthy experience for real users, but that is different from claiming that a contrast fix, keyboard fix or WCAG score directly increases authority in Search.

A better reporting model is to classify each finding by what it actually affects:

• User access: can someone perceive, understand or operate the page?
• Search discovery: can search engines reliably find the page or linked destination?
• Content understanding: does the markup or text make the topic, image or destination clearer?
• Task completion: can a person complete the intended action without avoidable friction?

This produces a more defensible audit than forcing every accessibility issue into an SEO narrative.

Do not treat an automated score as accessibility conformance

Crawlers, browser extensions and CI tools are valuable for finding repeatable problems at scale: missing attributes, contrast candidates, heading patterns, unlabelled controls and other machine-detectable issues. They cannot establish that a site is accessible on their own.

W3C is explicit that evaluation tools cannot check every accessibility aspect automatically and that human judgement is required. Use automated scanning as triage, then perform manual checks for keyboard behaviour, focus order, control purpose, alt-text quality, reading order, error handling and whether the experience actually makes sense. See W3C's evaluation-tool guidance.

Accessibility and SEO audit workflow

Use this order so the audit reduces real user risk first and captures genuine search overlap without wasting time on cosmetic fixes.

1. Inventory important templates and tasks. Include the homepage, navigation, article or product templates, search, forms, checkout or lead generation, account areas and any JavaScript-heavy interface.
2. Run automated checks at scale. Use a crawler and accessibility tooling to surface repeatable HTML-level issues, but label uncertain findings for manual review rather than treating them as confirmed failures.
3. Complete a keyboard pass. Traverse the full task, not just the header. Confirm logical focus order, visible focus, operable controls and no keyboard traps.
4. Review titles, headings and landmarks. Confirm the page title identifies the page, headings describe actual sections, and the structure remains understandable when scanned non-visually.
5. Classify images. Decide whether each image is informative, functional, complex, redundant or decorative before writing alt text. Do not generate keyword-heavy descriptions for every image.
6. Inspect links. Confirm important destinations use crawlable anchors, link text explains the destination, and image links have an appropriate accessible name.
7. Test forms and interactive states. Review labels, instructions, validation, errors, dialogs and status messages with both keyboard and assistive-technology considerations in mind.
8. Verify contrast and zoom/reflow behaviour. Check text, controls, meaningful graphics and key interaction states rather than testing only body copy.
9. Separate findings by impact. Mark issues as accessibility, search discovery, content understanding, task completion, or a genuine overlap. Do not inflate severity by calling every issue an SEO problem.
10. Retest after fixes. Re-run automated checks, then repeat the manual task. A clean scanner result is evidence that certain detectable issues were fixed, not proof of full WCAG conformance.

What to fix first

If the backlog is large, prioritise barriers that prevent people completing important tasks before lower-impact tidy-up work.

The practical goal is not to turn accessibility into an SEO tactic. It is to build pages that people can use and search engines can interpret, then be precise about where those outcomes genuinely overlap. That produces a stronger website and a more trustworthy audit than promising ranking gains from WCAG fixes that were designed for a different purpose.