Accessible website: Everything You need to Know

An accessible website is one you can perceive, operate and understand, whether or not you can see it, hear it, work it with a mouse, or move through it with a keyboard and a screen reader.

Key points

• An accessible website can be used by people with disabilities without help from anyone else.

• Four principles set the standard: perceivable, operable, understandable, robust.

• WCAG is the standard everything else refers back to. WCAG 2.2 is current, and level AA is the target almost every law and contract names.

• The three most common failures are weak contrast, missing alt text, and form fields with no label.

• An automated scan covers about a third of the criteria. The rest only shows up in a test with a keyboard, a screen reader and users.

Who digital accessibility matters to

The WHO estimates that 1.3 billion people, 16 % of the world's population, live with a significant disability. The group that benefits from an accessible site is larger still:

• Permanent limitations of sight, hearing, motor control or cognition

• Age-related change: eyesight, hearing and fine motor control decline gradually

• Temporary situations: a broken arm, an eye infection, a noisy room, sunlight on the screen

• Language: anyone reading in a language that is not their first

• Search engines and AI assistants, which read your page through structure, labels and text. Anything invisible to assistive technology is missing there too.

What is the Difference Between an Accessible and not Accessible Website

Two pages can look identical and behave completely differently for part of your audience. The difference usually sits one layer below the design.

What are the Four Principles of Accessibility

WCAG assigns every requirement to one of four principles. Their English names spell POUR.

Perceivable

Content is available through more than one sense.

• Alt text on images, captions on video, a transcript for audio

• Colour never carries information on its own: "the red fields are required" is useless to anyone who cannot tell red from green

• Contrast of at least 4.5:1 for normal text, 3:1 for large text

For what usable alt text looks like, see Alternative text (alt text)

Operable

Anything that works with a mouse works with a keyboard.

• Tab moves focus, Enter and Space activate, Escape closes

• Focus is visible at all times and follows reading order

• Targets are big enough to hit with a thumb

Understandable

The language, layout and behaviour of the page are predictable.

• Page language declared in the HTML

• Navigation in the same place on every page

• Errors explained in plain words, naming the field and the cause

Robust

The page works with the tools people actually use, including their next versions.

• Semantic HTML first, ARIA only where HTML has no suitable element

• Tested against screen readers, braille displays and voice control

• No functionality that depends on a specific browser or input device

What are the Common Barriers on Websites

WebAIM scans one million home pages every year. In February 2026, 95.9 % of them had detectable WCAG failures, 56.1 per page on average. Six error types accounted for 96 % of everything found.

None of these is exotic, and none of them starts in the code.

Missing alt text and weak contrast

Contrast fails in design, when a grey that is too light makes it into the style guide. Alt text fails in editing, when an image goes into the CMS in a hurry. Cheap to fix at the source, expensive across 400 pages later.

Elements you cannot reach with a keyboard

Empty links and empty buttons are silent to a screen reader: it announces "link" and cannot say where the link goes. The usual causes:

• Icons used as buttons with no text alternative

• Elements built as a div and made clickable with JavaScript, which the keyboard never reaches

• Custom dropdowns and modals that trap focus or lose it entirely

Testing this takes ten seconds. Put the mouse down, tab through the page, and check whether you can always see where you are.

Complex language and unclear forms

• Field with no label: if you cannot see what is expected, you fill it in wrong or give up

• No declared page language: a screen reader pronounces the text using the wrong language rules

• Long nested sentences, jargon, unexplained abbreviations: cost comprehension for everyone

WCAG and the laws that cite it

WCAG as the international benchmark

The W3C guidelines every accessibility law refers back to.

• Current version: WCAG 2.2, an official Recommendation since October 2023

• Older versions still count: 2.0, 2.1 and 2.2 are all valid, and laws differ on which they name

• WCAG 3.0 is an early draft with no publication date, so nothing requires it yet

• Structure: four principles, 13 guidelines, and success criteria you can test one at a time

Overview of the criteria: WCAG

The conformance levels A, AA and AAA

What "level AA" in a contract actually means.

• A is the floor. Failures here shut people out completely: a video with no captions, a form you cannot reach with a keyboard.

• AA is what almost every law and contract names. It adds the contrast thresholds, visible focus, reflow at 400 % zoom and captions for live audio.

• AAA is not meant for a whole site. WCAG itself says full AAA conformance is not a reasonable requirement for all content.

When a document says "accessible" with no more detail, read it as WCAG 2.1 or 2.2 at level AA.

Where WCAG turns into law

The standard itself is voluntary. The laws that cite it are not.

• EN 301 549 is the European standard for accessible ICT and points to WCAG level AA for web content. It is what an EU auditor tests against.

• The European Accessibility Act has applied to private providers across the EU since 28 June 2025: online retail, banking, passenger transport, e-books. Micro-enterprises with fewer than ten staff are exempt for services.

• The ADA names no technical standard itself. The Department of Justice's 2024 rule sets WCAG 2.1 level AA for state and local government sites, due April 2027 for larger entities and April 2028 for smaller ones. Private-sector litigation uses the same benchmark.

• National public-sector rules mostly require level AA too.

How to check whether your website is accessible

Three steps, and the first one is free.

1. Automated scan. Measures contrast and finds missing alt text, missing labels and structural errors in a few minutes.

2. Manual testing. Keyboard operation, screen reader, 200 % zoom, form journeys. No software can judge these. On why the two methods do not replace each other, read our manual vs automated accessibility testing article.

3. Audit with a report. A full website complience audit gives you a list sorted by severity, specific code guidance, and the basis for your accessibility statement.

read our content on how to make a website accessible for more information.

Rule of thumb: automated tools cover about a third of the criteria. A green scan means the obvious errors are gone, not that the site is usable.

7 free tools to check website accessibility

Every tool below is free, and each one covers a different part of the job. Pick one automated scanner rather than running all of them: they share much of the same rule set, so a second scanner mostly returns the findings you already have.

How to combine them. One scanner gives you the measurable errors in a few minutes. Add your keyboard and NVDA or VoiceOver on your three most important pages, usually search, checkout, and the contact form, and you'll find the barriers no scanner reports. If you want a first read across the whole site before you start, our free accessibility checker gives you the baseline in a few minutes.

What an accessible website costs

Three things drive the number:

1. How many page types you have: One corrected product template corrects 5,000 product pages with it.

2. How old the code is: A component library can be corrected centrally once; hand-built pages cannot.

3. Whether you are redesigning: Built into a relaunch, accessibility costs a fraction of a later repair.

For ranges and individual line items, see our pricing page.

FAQ about accessible websites

When does a website count as accessible?

When it meets every WCAG success criterion at level AA and can be operated fully with a keyboard and a screen reader. You evidence it with a test report and an accessibility statement. A badge or an overlay widget is not evidence.

Which content matters most?

Anything that leads to a completed action: search, product page, basket, sign-in, contact form, appointment booking. Downloadable documents count too, because an untagged PDF is a blank page to a screen reader.

What role do contrast, type size and colour play?

Contrast is the only one of the three with a fixed threshold: 4.5:1 for normal text, 3:1 for large text and interface elements. There is no minimum type size, but text has to zoom to 200 % without content disappearing. Colour must never be the only carrier of information.