Category: WCAG Principles and Conformance

Partial Conformance

Also known as: Statement of Partial Conformance

Simply put

Partial conformance is a way for a website author to acknowledge that a page mostly meets the Web Content Accessibility Guidelines (WCAG) but includes some content the author cannot fully control, such as media or features provided by a third party. Rather than claiming full conformance, the author can publish a statement describing which parts do not meet the requirements and why. This concept is defined by the W3C's Web Accessibility Initiative and is not a legal determination of compliance.

Formal definition

Partial conformance is an approach described in the W3C's Understanding Conformance documentation for pages that cannot meet WCAG conformance requirements because of content outside the author's control (for example, third-party embedded content) or content the author cannot fully account for at the time of publication. Because a full page that does not conform cannot claim full WCAG conformance, authors may instead publish a Statement of Partial Conformance identifying the non-conforming content and the reason. In documentation contexts such as a VPAT, related outcomes are commonly recorded by marking a success criterion as "Partially Supports" and adding a remark explaining the limitation. Partial conformance reflects a WCAG conformance-reporting mechanism rather than a measure of legal compliance or usability; this entry is not legal advice, and conformance claims should be evaluated against current W3C guidance and, where applicable, qualified counsel.

Why it matters

Partial conformance addresses a common real-world problem: many websites embed content they do not directly control, such as third-party media, advertising, social feeds, or user-generated material. When such content does not meet WCAG requirements, the page as a whole cannot claim full conformance, even if the author's own content does conform. The W3C's Statement of Partial Conformance gives authors a defined, transparent way to acknowledge these limitations rather than overstating a page's accessibility.

For compliance officers, legal counsel, and accessibility teams, this distinction matters because a partial conformance statement documents both what conforms and what does not, along with the reason. This transparency can support internal accountability and clearer communication with users who rely on assistive technology. It is important to understand, however, that partial conformance is a WCAG conformance-reporting mechanism defined by the W3C, not a legal determination. Publishing such a statement does not by itself establish compliance with the ADA, Section 508, or any other legal authority, nor does it guarantee an accessible experience for all users.

The concept also has a practical counterpart in procurement and documentation. In a VPAT, related limitations are commonly recorded by marking a success criterion as "Partially Supports" and adding a remark that explains the specific limitation. Organizations evaluating vendors or publishing their own conformance claims should treat these statements as descriptions of known gaps rather than assurances of full accessibility, and should consult qualified counsel where legal exposure is a concern.

Who it's relevant to

Accessibility Engineers and Web Developers

Developers who build pages that incorporate third-party media, embeds, or other content outside their direct control can use a Statement of Partial Conformance to accurately describe what conforms and what does not. The W3C advises choosing third-party products that meet WCAG requirements where possible, so partial conformance should be a documented acknowledgment of remaining gaps rather than a default posture.

Compliance Officers and Documentation Teams

Those preparing conformance reports, including VPATs, should understand that a partial conformance situation is commonly recorded by marking a success criterion as "Partially Supports" and adding a remark explaining the limitation. Accurate, specific remarks help stakeholders distinguish author-controlled gaps from third-party constraints.

Legal Counsel and Risk Advisors

Counsel should note that partial conformance is a WCAG reporting mechanism defined by the W3C, not a legal finding. It does not establish compliance under the ADA, Section 508, or other authorities, and it does not guarantee immunity from claims. Legal significance depends on jurisdiction, applicable regulation, and case law, and this entry is not legal advice.

Procurement and Vendor Management

Teams evaluating third-party products or services can use partial conformance statements and "Partially Supports" VPAT entries to identify known accessibility gaps before adoption. These disclosures describe limitations rather than resolve them, so they should inform remediation planning and vendor selection rather than serve as an assurance of full accessibility.

Inside Partial Conformance

Statement of Partial Conformance

WCAG defines a statement of partial conformance for content that does not fully conform but where the author wishes to make a conformance claim. It applies in specific situations rather than serving as a general-purpose claim of near-compliance.

Third-Party Content Scenario

One recognized basis for partial conformance addresses content the author cannot monitor or control at the time of publication, such as user-generated content or content injected by third parties, which may fall outside the author's ability to guarantee conformance.

Language/Technology Scenario

A second recognized basis addresses pages that cannot conform because a required accessibility-supported technology or language support is not available, which WCAG treats as a distinct circumstance.

Conformance Level Reference

Partial conformance statements are still framed against a WCAG version and level (commonly Level AA), and do not replace the underlying success criteria that would otherwise need to be met.

Scope and Disclosure

A meaningful partial conformance statement generally identifies which parts of the content do not conform and the reason, so users and evaluators understand the limits of the claim rather than treating it as full conformance.

Common questions

Answers to the questions practitioners most commonly ask about Partial Conformance.

Does claiming partial conformance mean my site is still WCAG conformant?

No. Partial conformance is not a WCAG conformance level in the way that A, AA, or AAA are. WCAG conformance is defined at the level of a full page or a set of pages, and a page that does not fully meet all applicable success criteria at a given level does not conform at that level. The concept of partial conformance in WCAG addresses limited situations, such as content contributed by third parties that is not under your control or content that cannot be fully evaluated at the time a conformance claim is made. Describing content as partially conformant should not be presented as equivalent to meeting the standard, and it does not by itself demonstrate legal compliance.

If I document partial conformance, am I protected from legal claims?

Not necessarily. Documenting partial conformance is a transparency and accountability practice, not a legal safe harbor. In the US, the ADA does not itself specify a WCAG version, and courts and settlements have often referenced WCAG as a benchmark rather than a codified rule; a partial conformance statement does not guarantee immunity from claims. Accessibility obligations evolve through regulation and case law and vary by jurisdiction and by which authority applies. This entry is general information, not legal advice, and you should consult qualified legal counsel regarding your specific situation.

When is it appropriate to make a partial conformance statement?

A statement of partial conformance is generally appropriate when a page includes content that is outside your control, such as third-party contributed content, or content that could not be fully evaluated at the time the claim was made. In these cases the statement should clearly identify what does not or may not conform and why, rather than being used to describe content the author controls but has not yet remediated.

How should partial conformance be documented?

Documentation should clearly identify the scope being described, the target WCAG version and conformance level being worked toward, which content is not fully conformant or could not be evaluated, and the reason. Being specific about the affected pages, components, or third-party sources helps readers and users understand the actual state of accessibility. Because WCAG conformance is defined for full pages and page sets, the documentation should make clear it is not asserting full conformance.

Does partial conformance apply to third-party or user-generated content?

It can. Content that is not under your control, including certain third-party or user-generated content, is one of the situations the partial conformance concept in WCAG is intended to address. Even so, organizations often take steps to influence what they can, such as setting requirements for vendors or moderating and remediating contributed content where feasible, while being transparent about remaining limitations.

Is meeting partial conformance enough to ensure an accessible experience?

No. Meeting WCAG success criteria, whether fully or partially, does not by itself guarantee an accessible experience for all users. Automated testing detects only a portion of potential issues, and manual testing along with assistive technology testing is generally required to evaluate real usability. Partial conformance describes a limited conformance status and should be paired with ongoing evaluation and remediation rather than treated as a finished state.

Common misconceptions

Partial conformance means the site is 'mostly compliant' and therefore legally safe.

Partial conformance is a narrowly defined WCAG concept for specific situations, not a general grade for how close a site is to conforming. Meeting or claiming any level of WCAG conformance does not guarantee immunity from legal claims, and legal exposure under authorities such as the ADA is determined through regulation and case law. This is not legal advice; consult qualified counsel.

You can claim partial conformance whenever some pages or criteria fail.

WCAG's statement of partial conformance is generally reserved for defined circumstances, such as uncontrolled third-party content or the unavailability of an accessibility-supported technology or language. It is not intended as a catch-all label for content that simply fails some success criteria.

A partial conformance statement is equivalent to a full WCAG conformance claim.

A partial conformance statement explicitly signals that the content does not fully conform. It does not satisfy the requirements of a full conformance claim, and it should disclose what does not conform and why.

Best practices

Verify that your situation matches a WCAG-recognized basis for partial conformance, such as uncontrolled third-party content or the unavailability of an accessibility-supported technology, before making such a claim.

Clearly state the WCAG version and target level (commonly Level AA) the content is measured against, and identify which parts do not conform and the reason.

Do not treat partial conformance as evidence of legal compliance; combine it with ongoing remediation and consult qualified legal counsel about obligations under applicable authorities.

Combine automated testing with manual and assistive technology testing, since automated checks detect only a portion of issues and cannot substantiate a conformance claim on their own.

Establish a process to monitor and remediate third-party or user-generated content over time so the scope of non-conformance narrows rather than persists.

Revisit partial conformance statements as content, technologies, WCAG versions, and applicable regulations evolve, since the basis for the claim may change.