Website Accessibility Best Practices: A Practical Guide

Accessibility issues can hide behind a great-looking website. Poor page structure, weak colour contrast, broken keyboard navigation, or missing screen reader support all get in the way of real people trying to use your site.

And you can't bolt accessibility on at the end. It has to be part of the site from the start, built in through development, then checked again and again as things change. Get into good habits early, and you'll catch most problems before they become expensive to fix.

This guide walks through the basics, including the four principles of accessibility, design best practices, the overlap with SEO, and maintaining high standards.

The four principles behind accessibility

Most accessibility guidance comes from the Web Content Accessibility Guidelines (WCAG). These are built around four principles, known as POUR:

• Perceivable: people need to be able to access the information on a page. Alt text for images and captions for videos are two examples.

• Operable: people should be able to navigate and use a website without a mouse.

• Understandable: content should be clear, with pages and interfaces behaving the way people expect.

• Robust: content should work across different browsers, devices, and assistive technologies.

These four principles are a useful lens for reviewing a site. Instead of treating every issue as its own isolated problem, they help you see why a change actually matters.

Design and structure best practices

Good accessibility starts with the basic structure of a page. That’s why you should start by using headings in a logical order. This lets screen reader users move between sections and understand how the content fits together.

Colour contrast matters too. To meet WCAG Level AA, normal-sized text needs a contrast ratio of at least 4.5:1. Fail to meet this basic requirement, and your website is already non-compliant with various accessibility legislation.

Here are a few more basics worth checking:

• Make sure keyboard users can see where the focus is on the page

• Use link text that explains where the link goes, not phrases like "click here"

• Write alt text based on what the image is for, not just what it shows

• Give form fields clear labels that are properly linked to the field, rather than relying on placeholder text

Oh, and don’t forget that using colour to communicate meaning alone is a big no-no. For example, if an error only shows up as red text, some people won't notice anything's wrong. In this instance, you’ll need to add an icon or a short line of text to ensure the message gets through to the end user.

The overlap between accessibility and SEO

Accessibility and SEO aren't the same discipline, but they overlap more than people think.
Clear headings help screen reader users move through content, while also giving search engines a clearer picture of how a page is structured. Descriptive alt text does the same thing, helping both the user and the crawler understand context hidden within images.

That doesn't mean fixing accessibility issues will automatically boost your rankings. The benefit is usually indirect. But it's still a good reason for SEO and accessibility teams to work from the same page, rather than treating these as two unrelated projects.

Testing and maintaining accessibility

Automated testing tools like Accessibility Checker catch roughly 50% of WCAG-related accessibility issues. That's a decent first pass, especially for large websites with thousands of pages to audit. But it won't catch everything. Manual testing is where the real problems show up. Try navigating your site with a keyboard only. Turn on a screen reader and attempt a core task, such as checking out or submitting a form.

Accessibility work doesn't stop after launch. New pages get added. Components get updated. Third-party embeds get bolted on. Any of these can quietly reintroduce issues. A recurring audit schedule, such as quarterly manual reviews and continuous monitoring with automated tools, stops standards from slipping without anyone noticing.

The final take: Don’t wait to work towards accessibility best practices

Accessibility isn't something you fix once and forget. It's a habit. Structure your content properly. Design with keyboard and screen reader users in mind. Keep testing after launch, not just before it. Do that well, and you end up with a site that works better for every visitor, and one that's on firmer ground with SEO and legal risk too.

Website accessibility best practices FAQs

What is website accessibility?

It means making a website that everyone can use, including people with visual, hearing, motor, or cognitive disabilities.

Is web accessibility a legal requirement?

Yes, in many countries. The ADA covers the US, the EAA applies across the EU, and the UK relies on the Equality Act.

What's the difference between WCAG 2.1 and WCAG 2.2?

WCAG 2.2 adds new success criteria, including better support for focus visibility, dragging alternatives, and touch target size on mobile.

Do accessible websites cost more to build?

Not usually. Building accessibility in from the start costs little extra. But retrofitting an existing site afterwards is far more expensive, so you actually save money in the long run.

Can accessibility lawsuits happen even if my site looks fine?

Yes, lawsuits often target technical issues invisible to sighted users, like missing alt text or broken screen reader support.