Isn't accessibility mostly about blind users?

No. Screen reader users are the group most people picture, but they are a minority of the affected population. Cognitive disabilities are the most commonly reported category in CDC survey data, and low vision is far more common than blindness. A program aimed only at screen reader support will pass a fraction of the criteria that matter.

How many people does this actually affect?

CDC puts it at roughly one in four U.S. adults living with a disability. But the more useful framing for a business is that situational and temporary limitations — bright sunlight, a broken arm, a noisy train, a bad connection — reach every user eventually, and are fixed by exactly the same work.

Can a scanner find these problems?

Only some. Automated tools are good at contrast ratios and missing attributes. They cannot tell you whether alt text is meaningful, whether a focus order preserves meaning, whether an error message explains the fix, or whether a voice command will actually activate a button. Most of what is on this page requires a person.

Which group should we fix for first?

Keyboard operability, if you have to pick one. It takes ten minutes to test, it blocks the most people the most completely, and the fixes it forces — real interactive elements, visible focus, sane order, no traps — resolve a large share of screen reader, switch, voice, and motor barriers at the same time.

Who It Affects

WCAG is a list of rules. This is the list of people it was written for.

The rest of this section is written for the people who buy accessibility work — deadlines, obligations, procurement, remediation cost. This page is the other half. Twelve profiles of who is actually blocked, what assistive technology they use, which success criteria fail them, and how to check your own site in about ten minutes.

Schedule Strategy Session Check Your Own Site Free

Blind and low-vision users navigating by audio or braille

People Who Use Screen Readers

A screen reader reads your markup, not your design. Everything meaningful you expressed visually has to also exist in code.

6 common barriers Users who magnify, restyle, or reformat pages to read them

People With Low Vision

Far more people have low vision than are blind. Most of them are not using a screen reader — they are using your page at 300% zoom.

6 common barriers Roughly one in twelve men and one in two hundred women

People With Color Vision Deficiency

Color can carry meaning — it just cannot be the only thing carrying it. This is the cheapest WCAG failure to fix and one of the most common.

4 common barriers Anyone who cannot rely on audio to receive information

Deaf and Hard of Hearing Users

Every piece of information you deliver by sound needs an equivalent in text. Auto-captions are a starting point, not a deliverable.

5 common barriers People who cannot use a mouse — by disability, by device, or by preference

Keyboard and Switch Users

If it works with a mouse but not with a keyboard, it does not work. This is the single highest-yield thing to test, and it takes ten minutes.

7 common barriers People who operate a computer by speaking to it

Voice Control Users

Voice control users say what they see. When the visible label and the accessible name disagree, the command fails silently.

4 common barriers Users affected by memory, attention, processing speed, or executive function

People With Cognitive and Learning Disabilities

The largest disability group and the least served by automated testing. Almost nothing here can be caught by a scanner.

7 common barriers Users for whom decoding text is effortful

People With Dyslexia and Reading Differences

Reading differences are common enough that designing for them is designing for a large share of your audience.

5 common barriers Users for whom animation causes dizziness, nausea, or migraine

People With Vestibular Disorders and Motion Sensitivity

Parallax, autoplay video, and large scroll-triggered animation can make someone physically ill. The fix is one media query.

4 common barriers Users for whom flashing content can trigger a seizure

People With Photosensitive Epilepsy

The smallest affected group and the highest-severity consequence on this entire list. There is no partial credit here.

3 common barriers Users experiencing several mild impairments at once

Older Adults

Aging rarely produces one disability. It produces slightly reduced vision, hearing, dexterity, and processing speed simultaneously — which compounds.

5 common barriers Everyone, eventually

Situational and Temporary Barriers

A broken arm, bright sunlight, a noisy train, a bad connection, a borrowed laptop. The accommodation is identical to the permanent one.

5 common barriers

The Part Most Programs Get Wrong

Conformance and accessibility are not the same thing.

A site can meet every Level A and AA success criterion and still be exhausting to use. Reduced-motion support is Level AAA. Plain language is Level AAA. Neither is required for conformance, and both change whether people can actually complete what they came to do.

That cuts the other way too. Passing a criterion is not the same as serving the person it was written for: alt text can be present and useless, a focus indicator can exist and be invisible against half your backgrounds, captions can be generated and wrong. Testing against the standard tells you whether you conform. Testing with the people on this page tells you whether it works.

All 55 Success Criteria

Test it yourself, today

Four checks that need no tooling and find most of what matters:

Unplug the mouse and complete your main task
Zoom to 400% and look for horizontal scrolling
Mute your most important video and see what you lose
Submit your longest form with everything wrong and read the errors

Then run the free checker for the parts a browser can measure.

A Note On The Numbers

Prevalence figures on these pages are floors, not estimates.

Every statistic cited here comes from public health survey data — CDC, NIDCD, the National Eye Institute, WHO. Survey data on disability undercounts, consistently and for understandable reasons: people with mild or recent impairments frequently do not identify as disabled, and many of the users most affected by the barriers on these pages would not check the box. Older adults are the clearest case. They rarely describe themselves as having a disability, they rarely request accommodations, and when a site fails them they overwhelmingly assume the fault is theirs.

Use these numbers for scale — to establish that none of this is an edge case — rather than for precision in a proposal. If you need defensible figures for a business case, the honest version is your own analytics: form abandonment by step, support ticket volume by task, and the share of users who start a transaction online and finish it on the phone.