The Overlap Between Accessibility and SEO Wins

Here’s a useful trick for anyone who has to argue for budget: find two things people want for different reasons, and notice when they’re secretly the same thing. Accessibility and SEO are the best example of this I know on the web. One is framed as ethics and compliance, the other as growth and traffic. They report to different people, get funded from different budgets, and are argued for in completely different vocabularies. And yet if you write down the list of fixes each one demands, the lists overlap so heavily you could staple them together.

The overlap isn’t a coincidence. It comes from a structural fact: a screen reader and a search crawler are both non-visual consumers of your page. Neither can see your layout. Both have to reconstruct your page’s meaning from its markup. So anything that makes a page more legible to one tends to make it more legible to the other. They are, in a sense, the same user with different motivations. One wants to read your page aloud to a person; the other wants to file it in an index. Both are stuck working from the same raw material, and both fail in the same places.

Walk through the classic accessibility checklist and watch it turn into an SEO checklist. Alt text on images exists so a screen reader can describe a picture to someone who can’t see it. It’s also the main way an image ranks in image search, and a signal about the surrounding content. A logical heading hierarchy exists so a blind user can skim your page by jumping between headings, the way a sighted user skims by eye. It’s also how a crawler builds an outline of your page and decides what it covers. Descriptive link text exists because hearing “click here, click here, click here” out of context is useless. It’s also anchor text, which search engines have treated as a description of the destination for as long as they’ve existed. Even proper form labels, which seem purely about usability, tell a machine what your inputs collect. Every entry on the list serves both audiences, because both audiences are blind.

What I find most interesting is what this overlap tells you about which advice to trust. SEO is a field with a signal-to-noise problem. There’s an ocean of tactical advice, much of it folklore, some of it actively harmful, and the ranking algorithms it targets change constantly. Accessibility advice, by contrast, is anchored to something stable: WCAG, the Web Content Accessibility Guidelines, which change slowly and are grounded in how assistive technology actually works. So when a piece of SEO advice coincides with an accessibility requirement, you can be fairly confident it’s real, because it’s justified by two independent lines of reasoning. Headings matter for SEO? Also a WCAG concern; probably durable. Some tactic about keyword placement density that helps no human? No accessibility analog; treat it with suspicion. The overlap works as a filter for separating web fundamentals from ranking folklore.

There’s an economic argument hiding here too. Accessibility work is chronically underfunded because its benefits are hard to attribute; you rarely get a dashboard showing revenue from users who could suddenly use your site. SEO work is chronically overfunded relative to its rigor because traffic is measurable and everyone wants more of it. If you’re the person who cares about accessibility inside a company that only funds growth, the overlap is your lever. You don’t have to win the moral argument. You can point out that the fix you want, adding alt text, repairing the heading structure, making links descriptive, is also on the SEO team’s list, and get it funded twice as easily. Some people find this framing cynical. I find it practical. The users get the accessible site either way.

I see the overlap concretely in GazeSite’s output. It grades sites across six areas, and accessibility and SEO are scored separately, by design, because they’re different questions: can everyone use this, and will the right people find it. But the findings rhyme. A page with no H1 usually also has a broken heading hierarchy. A page with vague titles usually has vague link text. The two columns of the report keep pointing at the same underlying markup, one fix showing up twice under two names. When one fix improves two scores, that’s not double counting. That’s the overlap, measured.

The deeper lesson is about what both disciplines are approximations of. A page that a blind user can navigate and a crawler can parse is a page whose structure matches its meaning. That’s not an accessibility property or an SEO property. It’s just quality, viewed from two angles. The overlap between the two checklists is the shadow that quality casts. Chase either one honestly and you end up building the same thing: a page that says what it means to anyone, or anything, that asks.