A major benefit of prioritising web accessibility is its impact on search engine optimisation (SEO) — often in ways that are both surprising and substantial.
At first, you might assume it’s a small influence, but the overlap between accessibility and SEO is more significant than many realise.
Let’s break it down.
A core pillar of web accessibility is the acronym POUR. Content should be:
Perceivable - Information and user interface elements must be presentable to users in ways they can perceive, regardless of sensory abilities.
Operable - User interface components and navigation must be operable through various means, not requiring interactions that users cannot perform.
Understandable - Information and interface operation must be understandable, with content and operation within users' comprehension.
Robust - Content must be robust enough to be reliably interpreted by various user agents, including assistive technologies, and remain accessible as technologies advance.
You can argue that the above principles are important in SEO too. I mean, who wouldn’t want their digital products to meet each criterion?
Below are the different aspects of SEO and how they directly influence the POUR principles. Alternatively, you can click on the links below to skip to the relevant sections.
Alternative text.
Alternative text (alt text) plays a crucial role in both accessibility and SEO. When you provide descriptive alt text for images, you help screen reader users understand the content while also giving search engines valuable context about your visuals, which improves your visibility in image search results.
HubSpot’s quest to improve their image SEO using alt texts has increased their image organic search traffic by 779% (Opens in a new window) . 😳
Proper heading structure (H1-H6).
The proper use of heading structure creates a clear content hierarchy that benefits both users and search engines. Headings act as a roadmap for your content - they help users scan and navigate your page while simultaneously signalling to search engines the relative importance of different sections.
A well-structured and accessible heading hierarchy (Opens in a new window) can improve your page's accessibility score and search engine rankings.
Captions and transcripts have multiple uses.
Captions and transcripts serve various purposes for multimedia content like videos and podcasts. They make your content accessible to deaf or hard-of-hearing users and provide search engines with additional text to index and create more opportunities for your page to appear in relevant search results, expanding your content's reach.
And don’t forget, captions benefit many people, not just those who are deaf and hard of hearing.
Good colour contrast and readable text.
Colour contrast and text readability are not just visual concerns; they have broader implications. When users can easily read and engage with your content, they are more likely to spend time on your page and interact with it.
Unfortunately, it is common to see the colour contrast between text and background making it impossible. In fact, a 2024 research by WebAIM on the top one million pages found that low contrast amounts to 81% of homepages, making it the most common Web Content Accessibility Guidelines 2 (WCAG 2) failure.
Since Google emphasises user experience, readable, high-contrast text benefits accessibility and SEO.
Keyboard navigation improves the crawlability for search engine bots.
Keyboard navigation is a fundamental aspect of web accessibility (Opens in a new window) that benefits your SEO efforts. When your site is structured for keyboard navigation using the likes of headings and semantic HTML, you create a clear path for search engine crawlers.
Without proper keyboard navigation and structure, users dependent on it will find themselves “keyboard trapped” (Opens in a new window) where they are unable to move to or from a page element when navigating using a keyboard.
Descriptive anchor text helps search engines understand page relationships and context.
Rather than using generic phrases like "click here" or "read more," meaningful anchor text (Opens in a new window) helps users and search engines understand a link's destination.
For example, instead of "click here to learn more", use "explore our web accessibility services". This context-rich approach aids user navigation and helps search engines understand your pages' relationships and overall content context.
A SEMrush study found that using anchor text variations can improve rankings, with a 2% increase for pages with a high percentage of anchor text variations.
Skip links help search engines better understand page structure.
Skip links, whilst primarily an accessibility feature (Opens in a new window) , also serve an SEO purpose and benefit everyone else too. These links allow users to bypass repetitive content (like navigation menus) and jump directly to the main content.
From an SEO perspective, this helps search engines better understand your page structure and hierarchy, distinguishing between navigation elements and primary content. It also makes it more engaging by allowing your audience to interact with your page and get to where they want quickly.
More time on your website means fewer bounce rates, which improves engagement signals.
When users have adequate time to engage with your content, they're less likely to return to search results. Lower bounce rates and higher engagement times send positive signals to search engines about your content's quality and relevance, potentially improving your search rankings.
Clear language and readability improve user engagement metrics.
Clear language and readability don't just make your content accessible—they're fundamental to your SEO success (Opens in a new window) . When you write in plain, easy-to-understand language, you naturally increase user engagement metrics like time on page and reduce bounce rates.
Search engines interpret these metrics as signals of content quality, potentially boosting your rankings. One way of doing that is to write clearly and for humans, as that will incorporate relevant keywords naturally.
This also crosses over with the earlier points about implementing correct heading structure, as that can have an impact on the readability of a typical page.
Consistent navigation helps search engines understand site structure.
Navigation consistency across your website serves dual purposes. It creates a predictable experience for us all that helps us find what we need.
Consistent navigation provides clear pathways to crawl your site and understand its structure for search engines. This helps them build a more accurate site map and understand the relationships between different pages on your site.
This can apply to both traditional top navigation and breadcrumb navigation, a type of navigation that shows users their current location within a website's hierarchy, like "Home > Products > Electronics".
Clear page titles and headings improve CTR from search results.
Page titles and headings play a crucial role in both accessibility and search performance. Well-crafted titles and headings help users understand what content to expect and directly impact your click-through rates (CTR) from search results.
A clear, compelling page title (Opens in a new window) that accurately describes your content is likely to attract clicks from search results pages. Search engines take note of these positive user interactions.
Logical content organisation helps search engines understand topic relevance.
The logical organisation of content on your pages helps search engines understand topic relevance and context.
When you structure your content in a clear, hierarchical manner, moving from broad topics to specific details, you make it easier for users to follow along and help search engines better understand the relationships between different concepts on your page.
This improved understanding can lead to better search result positioning for relevant queries.
And you know what else can help with that? Headings. Did I mention the importance of clear and well-structured ones? 👀
Clean, semantic HTML helps search engines parse content.
Clean, semantic HTML (Opens in a new window) serves as the foundation for robust accessibility and effective SEO.
When you use proper HTML elements for their intended purposes – like using <nav> for navigation and <article> for main content – you're making it easier for search engines to parse and understand your content.
This clear structure helps search engines determine the relative importance of different page elements and index your content more accurately.
Mobile responsiveness is a ranking factor.
This is old news in SEO, but in today's digital landscape, mobile responsiveness has become non-negotiable.
A responsive design that works seamlessly across all screen sizes serves your users better, including those who are dependent on assistive technology. As well as being a critical part of SEO, it is equally critical in accessibility and WCAG (Opens in a new window) .
Fast loading speeds, achieved through clean code, influence rankings.
Search engines have made it clear that site speed is a ranking factor, with Google including it in their Core Web Vitals metrics (Opens in a new window) , a set of specific performance metrics that measure the user experience of a website.
When your code is clean and well-structured, it typically leads to faster loading times, benefiting both your accessibility compliance and search rankings.
There are many ways to achieve faster loading speeds, like reducing image sizes. But add it all up, and combine that with maintaining clean code, will play a part together.
Valid markup helps search engines and screen readers interpret page content correctly.
When your HTML is valid and properly structured (Opens in a new window) , search engines and assistive technology like screen readers can more confidently parse your content and understand its context, leading to better rankings for relevant searches.
Let’s make one thing clear; accessibility is not a direct ranking factor. John Mueller, Senior Webmaster Trends Analyst and Search Relations team lead at Google, discussed this in an interview on the Google Search Central YouTube channel in 2022.
Although it’s not a direct ranking factor, Google takes it seriously. Their Lighthouse tool, which audits site performance, SEO, and many more, also scores accessibility as a key element of overall web page quality.
In the early days of SEO, there was a lot of emphasis on gaming Google’s algorithm to gain higher ranking. But that often came at the expense of good quality web pages and experience for humans. So it’s not worth it.
Nowadays, there is a huge emphasis on focusing on people, not bots.
One thing for sure is that accessibility is always about people.
Always.