Web Accessibility and Conversion: EAA Guide

Since June 28, 2025, selling online to consumers in the European Union requires meeting accessibility standards. The European Accessibility Act (EAA) has turned what was long considered a best practice into a legal obligation. For marketing and product teams, it raises a very concrete question: what happens to conversion if we change colours, buttons, and copy to comply?

What the regulation says and who it affects

The EAA is Directive (EU) 2019/882, which the European Commission summarises here. In Spain it was transposed through Law 11/2023 of May 8. It applies, among others, to ecommerce, consumer banking services, passenger transport services (websites, apps, and electronic tickets), and ebooks. Micro-enterprises providing services, with fewer than 10 employees and an annual turnover or balance sheet of up to 2 million euros, are exempt.

The usual technical reference is EN 301 549, which aligns with the AA level of the WCAG 2.1 accessibility guidelines. This article is not legal advice. If you have questions about your specific situation, consult a specialist.

The most common violation is also the most visible

The annual WebAIM Million analysis reviews the one million most visited homepages. Its 2025 edition found WCAG failures on 94.8% of them, and the most frequent issue was low-contrast text, present on 79.1%.

Level AA requires a minimum contrast ratio of 4.5:1 for normal text and 3:1 for large text and UI components. Many vivid brand colours — oranges, yellows, light greens — fall short of that ratio when paired with white text. And those tend to be exactly the colours used for purchase buttons.

The WCAG guidelines that affect conversion the most

WCAG has dozens of criteria, but not all of them weigh equally on the pages where the sale is decided. From a CRO perspective, these are the ones worth reviewing first.

• Text and button contrast, already mentioned, is the most visible. It affects the main CTA, prices, and the legal text that accompanies payment.
• Form labels come second. A field that only shows placeholder text inside the input — text that disappears when you start typing — forces the user to remember what was being asked. It is a problem for screen readers, but also for anyone who gets distracted halfway through checkout. A visible label above the field solves both issues.
• Error messages come third. WCAG requires errors to be identified and described in text, not just with a red border. A message that says "enter a 5-digit postal code" helps more than one that says "invalid field", and reduces the repeated corrections that end in abandonment.
• Visible keyboard focus is fourth. Many sites remove it for aesthetic reasons. Without it, a user navigating with the Tab key has no idea which button is active.
• Fifth is the size and spacing of touch targets. WCAG 2.2 introduces a minimum target size, and on mobile, buttons that are too small or too close together cause mis-taps on quantities, sizes, or payment methods.

The fear: "if I change the button colour, sales will drop"

It is a reasonable fear. The CTA colour is often a brand decision that has been defended for years. At Dogfy Diet, which operates in Spain, France, Italy, and Germany, we decided to settle it with data.

In a test applied across the entire site on mobile and desktop, we replaced the vivid orange of the CTAs with a darker tone offering higher contrast. The hypothesis was framed in an unusual way: we were not trying to improve, but to verify that the change did not hurt performance.

Version	Visitors	Form entries	Form entry rate
Control (vivid orange)	5,671	1,929	34.02%
Variant (darker tone, higher contrast)	5,493	1,894	34.48%

The expected uplift was +1.37%, with a 53.34% probability in favour of the variant. In practice, that means there was no detectable difference — which was exactly what we needed to prove. The colour change required by the regulation did not penalise funnel entry.

Why test a change you are going to make anyway

If the change is mandatory, why test it? For three reasons. First, there is almost always more than one way to comply, and the test tells you which one best preserves conversion. Second, if a particular implementation hurts performance, you know before rolling it out to all traffic. Third, it is documented for other markets and teams.

The key is in the test design. Before launching, you need to set the maximum acceptable loss rather than look for a winner. That is the logic of a non-inferiority test, and it completely changes how you read a "no winner" result.

Accessibility is also market share

According to the World Health Organisation, around 1.3 billion people — roughly 16% of the global population — live with a significant disability. On top of that come situational limitations that affect everyone: a screen in direct sunlight, a phone used one-handed, tired eyes... Improving contrast, form labels, or keyboard navigation benefits all of those users.

We are not going to promise that accessibility will skyrocket conversion: our data does not show that. What it does show is that compliance does not have to cost you sales if you approach it with the right method.

Where to start applying the mandatory accessibility guidelines

Start with the pages where the sale is decided: product detail, cart, checkout, and forms. On those pages, check the contrast of buttons and text, make sure fields have visible labels, that errors are explained in text, that focus is visible when navigating by keyboard, and that relevant images have alt text. Then prioritise changes by funnel impact and validate the ones that affect conversion elements with a test.

A Scan&Boost audit is a good first diagnostic of the visual and mobile experience. If you already know what you want to change, working with our full CRO method lets you validate it with tests in a matter of weeks.