What is web accessibility?
Web accessibility is about everyone being able to use a website, including someone who sees poorly, cannot use a mouse or navigates with assistive technology. Since 2025 it is also a legal requirement for many private services, not just for the public sector. This guide goes through what WCAG and the law require, the four core principles, and where to start without rebuilding everything.
By Simon Torngren · Partner and COO· Published · Updated Our view
Accessibility is a basic requirement on the web, not a bonus added afterwards. What makes a site usable for more people (clear structure, good contrast, text that can be navigated) makes it better for everyone, and cheapest to build in from the start. See it as part of the quality, not a checklist at the end.
What web accessibility is.
Web accessibility means a website can be used by as many people as possible, regardless of ability or assistive technology. It covers people with reduced sight or hearing, people who cannot use a mouse and navigate with a keyboard, and people who use screen readers that read out the content. But it equally covers the person sitting in bright sunlight, who has broken an arm or is using a slow phone.
The foundation is a standard called WCAG, the Web Content Accessibility Guidelines, produced by the web's standards body W3C. WCAG is divided into three levels: A is the minimum, AA is the practical target level that laws and procurement refer to, and AAA is the strictest and rarely a realistic requirement for a whole site. When someone says a site should be accessible, in practice they almost always mean WCAG level AA.
W3C's WCAG standard↗ is the source, but it is extensive. The important thing to start with is the principle: an accessible site is a site more people can use, coded so that both humans and assistive technology understand it.
The four principles.
WCAG rests on four principles, often shortened to POUR. They are easier to work from than the long list of criteria, because they describe what accessibility actually means:
- Perceivable. The content must be possible to perceive even if one sense does not work. Images need alternative text, video needs captions, and text needs sufficient contrast against the background.
- Operable. Everything must be controllable, not just with a mouse. The page must be navigable with a keyboard, and nothing should require movements or time limits that shut certain users out.
- Understandable. Text and functions must be easy to understand and predictable. Clear language, consistent navigation and understandable error messages in forms belong here.
- Robust. The code must work with different browsers and assistive technology, today and going forward. It is built on semantic HTML: describing what each part actually is, so that a screen reader can interpret it correctly.
The principles overlap with things that improve a site anyway: semantic HTML helps both screen readers and search engines, and clear language benefits everyone. Accessibility is rarely a separate track alongside quality, it is part of it.
What the law requires.
Accessibility has gone from recommendation to legal requirement. The public sector in Sweden has for some time been covered by the DOS Act, the law on accessibility to digital public services, which requires the websites of authorities and municipalities to follow WCAG level AA. The DIGG agency supervises it, and the guidance is gathered at webbriktlinjer.se.
The big shift is that the requirements now also cover the private sector. The EU accessibility directive, often called the European Accessibility Act, took effect on 28 June 2025 and covers many private products and services: e-commerce, banking services, ticket sales and more. For a large part of the business world, accessibility is therefore no longer optional.
Webbriktlinjer.se↗ and DIGG's guidance↗ are the Swedish sources to work from. Exactly what applies to your particular operation depends on industry and service, but the direction is unambiguous: the bar is being raised, not lowered. Building accessibly is cheaper than fixing it afterwards under time pressure.
Where to start.
Most accessibility problems are common, well known and fairly cheap to fix, especially if you take them early. Start with the shortcomings that shut out the most people:
- Contrast. Light grey text on a white background is beautiful and unreadable for many. Sufficient contrast between text and background is one of the simplest and most effective fixes.
- Alternative text on images. Images that carry information need a describing text so that screen readers can convey them. Purely decorative images should conversely be skipped.
- Keyboard navigation. Everything that can be done with a mouse must be doable with a keyboard, and it must be visible where the focus is. Test it by putting the mouse aside and tabbing through the page.
- Heading structure and forms. Headings in the right order give the screen reader a map of the page, and form fields with clear labels and understandable error messages make the difference between being able to buy and giving up.
Building this in from the start costs little. Fixing a finished site afterwards costs much more, because accessibility often sits in the structure rather than on the surface. That is why accessibility belongs in the requirements when the site is built, not as a review at the end.
Why it benefits everyone.
There is a misconception that accessibility is a service for a small group. In fact it is a clear example of what is called the curb-cut effect: the ramp in the kerb was built for wheelchairs, but is used by everyone with a pram, a suitcase or a bike. The same thing on the web. Captions help the person who cannot hear, and the person watching with the sound off. Clear structure helps the screen reader, and the stressed person skimming.
On top of that, accessibility overlaps with things you want anyway. Semantic HTML and clear headings help search engines understand the site, fast and stable code benefits both assistive technology and performance, and understandable forms raise conversion for everyone. Accessibility is rarely a cost on the side, it is quality that happens to have a legal and human upside thrown in.
So accessibility is decision support, not a tick in a box: a site more people can use is a better site, often with better search and higher conversion. If you want a site built or reviewed against WCAG, see how Memorise works with web, or read on about web development as a whole.
Want to know how accessible your site is?
Send us your web address, and we will do an overview review against WCAG level AA: where the site shuts users out, what is a legal requirement and what is easy to fix first. You get a concrete picture to prioritise from.
Write to us →Common questions about web accessibility
What is web accessibility?
Web accessibility means a website can be used by as many people as possible, regardless of ability or assistive technology. It covers people with reduced sight or hearing, people who navigate with a keyboard or screen reader, but also everyday situations like bright sunlight or a slow connection. The foundation is the WCAG standard.
What is WCAG level AA?
WCAG is the international standard for web accessibility, divided into three levels: A, AA and AAA. AA is the practical target level and the one laws and procurement refer to. It covers things like sufficient contrast, alternative text, keyboard navigation and clear structure. AAA is stricter and rarely a realistic requirement for a whole site.
Does our website have to be accessible by law?
For many operations, yes. The public sector has been covered by the DOS Act for some time. Since 28 June 2025 the EU accessibility directive also covers many private services, such as e-commerce and banking. Exactly what applies depends on industry and service, but for a large part of the business world accessibility is now a legal requirement, not something optional.
What does it cost to not be accessible?
It comes down to three things: legal risk if the operation is covered by the requirements, lost customers who cannot use the site, and more expensive fixes later. Fixing a finished site afterwards costs more than building it right from the start, because accessibility often sits in the structure. The cheapest route is to include it in the requirements when the site is built.
Does accessibility help SEO too?
Yes, they overlap. Semantic HTML and clear heading structure help both screen readers and search engines understand the site. Alternative text describes images for both assistive technology and Google. Fast, stable and understandable code benefits accessibility, performance and search at the same time. Accessibility work often improves findability as a side effect, even if that is not the main purpose.