EN 301 549 Annex C is the normative annex titled "Determination of conformance." It is the part of the standard that turns each requirement into a checkable pass/fail test. Every requirement in the main clauses is written with a pre-condition (the text "Where ICT «pre-condition»") and Annex C pairs that pre-condition with a corresponding test. Conformance to a requirement is achieved when the pre-condition is true and the test is passed; when the pre-condition is false, the requirement simply does not apply (ETSI EN 301 549 v3.2.1). That mechanism is why Annex C matters. EN 301 549 is the harmonised European standard the European Accessibility Act and the earlier Web Accessibility Directive rely on for a presumption of conformity, and Annex C is how an auditor decides, requirement by requirement, whether a product actually meets it. One caution up front: Annex C is not a step-by-step testing methodology. It tells you the condition that counts as a pass, not how to drive a screen reader or read a spec. Some of those tests a scanner can settle; many still need a person. This guide explains what Annex C contains, how it sits alongside Annex A's presumption tables, and what it means for documenting where you stand.
What is EN 301 549 Annex C?
Annex C is the normative annex of EN 301 549 that sets out the means necessary to determine conformance with the individual requirements in the main body of the standard (ETSI EN 301 549 v3.2.1). "Normative" is the key word: it is part of the standard you have to meet, not background reading. Where clauses 4 through 13 state what a requirement is, Annex C states when you have met it.
The main body of EN 301 549 covers a wide surface of information and communication technology: hardware, non-web software, native mobile apps, documents, closed-functionality products such as ticket machines, telecoms features like real-time text, and, in Chapter 9, web content. Chapter 9 is where the standard adopts WCAG 2.1 Level AA wholesale (ETSI EN 301 549 v3.2.1). Every one of those requirements, web and non-web alike, has a matching entry in Annex C that says how to judge conformance.
How does Annex C actually work?
It works through a pre-condition and a test. Requirements in EN 301 549 are phrased as "Where ICT «has some feature», it shall «do something»." Annex C reads that structure and turns it into a decision: is the pre-condition true for this product, and if so, does the product pass the corresponding test?
There are three possible outcomes for any given requirement. If the pre-condition is true and the test passes, the requirement is met. If the pre-condition is true and the test fails, it is not met. And if the pre-condition is false, the requirement is not applicable to that product at all (ETSI EN 301 549 v3.2.1). That third outcome matters more than it looks. A website with no video does not fail the captions requirement; the pre-condition ("Where ICT displays video with audio") is false, so the requirement drops out of scope. Annex C is what makes "not applicable" a defined result rather than a judgment call.
For web content, the tests in Annex C route back to WCAG. Because Chapter 9 incorporates the WCAG 2.1 AA success criteria, the Annex C test for a clause like 9.1.4.3 is, in effect, the WCAG test for 1.4.3 Contrast (Minimum). The clause numbers even line up: EN 301 549 clause 9.X.Y.Z is WCAG success criterion X.Y.Z with a "9." prefix. For hardware, documents, and telecoms features, the tests describe conditions WCAG never covers.
What's the difference between Annex A, Annex B, and Annex C?
They answer three different questions, and it helps to keep them apart.
| Annex | Question it answers | What it contains |
|---|---|---|
| Annex A (informative) | Which requirements earn a presumption of conformity? | Tables A.1 (web pages and documents) and A.2 (mobile apps) that map the standard's clauses to the Web Accessibility Directive |
| Annex B | Which requirements serve which user need? | A table linking the requirements in clauses 5–13 to the functional performance statements in clause 4 |
| Annex C (normative) | Have I met each requirement? | The pre-condition and pass/fail test for every requirement |
Annex A is the one people mean when they say "presumption of conformity." Its tables list the clauses that, when met, confer a presumption of conformity with Directive (EU) 2016/2102 for public sector web pages, documents, and mobile apps (ETSI EN 301 549 v3.2.1). A detail worth knowing: requirements that are part of EN 301 549 but not listed in Table A.1 or A.2 are still part of the standard, they just do not carry that presumption. So Annex A defines the legal shortlist, and Annex C tells you whether you have passed each item on it.
Why does Annex C matter for the EAA?
Because the EAA runs on the same presumption-of-conformity mechanism, and Annex C is where a claim of conformity is settled. The European Accessibility Act became applicable to new products and services on 28 June 2025, and economic operators can use the harmonised standard EN 301 549 v3.2.1 to demonstrate compliance (European Commission). Applying a harmonised standard cited in the Official Journal gives a presumption that you meet the law's essential requirements. Annex C is the yardstick behind that presumption: the requirement-level tests you either pass or do not.
This is also where an accessibility statement gets its evidence. A statement documents your level of conformance and your known limitations, and Annex C gives you the per-requirement result (met, not met, or not applicable) to base that on honestly. Working requirement by requirement through Annex C is what turns "we think our site is accessible" into a defensible record of what was tested and what the outcome was. Our WCAG checklist maps the web-content side of that work to WCAG 2.1 AA, which is exactly the set of tests Annex C points to for Chapter 9.
Can an automated scanner satisfy Annex C on its own?
No. Annex C is not a testing methodology, and a scanner cannot settle most of it alone. The annex tells you the condition that counts as a pass; it does not walk you through performing the test, and you still need to understand the functional performance statements and the testing procedures to apply it (ETSI EN 301 549 v3.2.1).
Some Annex C tests are machine-decidable. A scanner can measure contrast ratios or find images without a text alternative. Many are not. Deque's analysis of more than 2,000 audits found automation identified about 57% of issues by volume, while estimates based on the share of success criteria a tool can even evaluate put the figure closer to 30% (Deque). Judging whether focus order is logical, whether an error message is actually helpful, or whether a caption is accurate takes a person testing with a keyboard and a screen reader.
No scanner, and no overlay widget, can confirm conformance to Annex C by itself. Claiming otherwise is what earned the overlay vendor accessiBe a $1 million order from the US Federal Trade Commission for representing that its product made sites WCAG compliant (FTC). The workable route is to let a scanner clear the machine-detectable tests, review the rest by hand, and record the Annex C outcome for each.
Is Annex C changing in the next version?
Yes, along with the rest of the standard. A draft, EN 301 549 v4.1.0, was released for public comment in November 2025, and the final v4.1.1 is expected to be referenced in the Official Journal around October 2026, after which it would replace v3.2.1 (ETSI EN 301 549 v4.1.0 draft). The main change for the web is that Chapters 9, 10, and 11 move up to align with WCAG 2.2, which adds success criteria on top of 2.1. As the requirements change, their Annex C tests change with them.
Until that version is cited in the Official Journal, v3.2.1 and WCAG 2.1 AA remain the reference, and its Annex C is the one that applies. The sensible planning position is to test against v3.2.1 today while reading WCAG 2.2's additions so the eventual step up is small.
Frequently asked questions
Is Annex C normative or informative?
Normative. Annex C, "Determination of conformance," is a required part of EN 301 549 that defines how conformance to each requirement is judged. By contrast, Annex A, which holds the presumption-of-conformity tables, is labelled informative in v3.2.1.
What does a "pre-condition" mean in Annex C?
It is the "Where ICT «...»" clause attached to a requirement. If the pre-condition is true for your product, you have to pass the corresponding test. If it is false, the requirement does not apply, so a feature you do not have never counts as a failure.
Does Annex C tell me how to test my website?
Not step by step. Annex C gives the pass/fail condition for each requirement, not a procedure for running the test. You still need to know how to test with assistive technology and how to read the functional performance statements to apply it.
Is Annex C the same as the presumption of conformity?
No. The presumption of conformity comes from Annex A's tables, which map clauses to the relevant EU directive. Annex C is how you determine, requirement by requirement, whether you have actually met those clauses.
Which version of EN 301 549 does Annex C apply to today?
Version 3.2.1, published in March 2021. It is the harmonised standard currently referenced for the EAA and the Web Accessibility Directive. A v4.1.1 update aligned with WCAG 2.2 is expected to be cited in the Official Journal around October 2026.
Test the web-content side of Annex C first
For most teams, the largest block of Annex C tests sits in Chapter 9: the WCAG 2.1 AA criteria for web content. That is the practical place to start. Run a free scan to clear the machine-detectable checks on your key pages, then work through the manual criteria a scanner cannot judge. You will have real, requirement-level results to record in an accessibility statement, instead of a guess about where you stand.
Pavel Charkasau, founder, wcagc.com. Last updated 5 July 2026.
Sources
- EN 301 549 v3.2.1 (2021-03), ETSI — Annex C "Determination of conformance" (pre-condition and test, pass/fail/not-applicable), Annex A tables A.1 and A.2 and the presumption of conformity, and Chapter 9 incorporation of WCAG 2.1 AA. Accessed 5 July 2026.
- Draft EN 301 549 v4.1.0 (2025-11), ETSI — draft update aligning Chapters 9, 10, and 11 with WCAG 2.2. Accessed 5 July 2026.
- Web accessibility standards — latest changes, European Commission — EAA applicable 28 June 2025, EN 301 549 v3.2.1 as the harmonised standard, and the expected v4.1.1 Official Journal citation. Accessed 5 July 2026.
- Automated testing identifies 57% of accessibility issues, Deque — automated coverage figures. Accessed 5 July 2026.
- FTC approves final order requiring accessiBe to pay $1 million, Federal Trade Commission — deceptive WCAG-compliance claims. Accessed 5 July 2026.