What is PDF/UA and why it matters for PDF accessibility
What makes a PDF accessible? How do assistive technologies know what’s on the page? Two files share the .pdf extension, yet only one invites everyone in. PDF/UA is the standard that makes the difference. Here’s what you need to know.
The importance of universal PDF accessibility
PDFs are a widely used digital format. Millions of organizations and individuals use them to exchange information, and they make up a large share of documents published online. Because the format is so widespread, equal access to its content is essential.
For people who navigate with screen readers, Braille displays, or alternative input devices, access largely depends on the PDF including semantic tags and key attributes that describe the document. With that information, assistive technologies can present the content in the intended order and with the correct meaning.
The PDF/UA set of standards (ISO 14289) defines the structural, tagging, and metadata requirements for making PDFs universally accessible.
Key requirements of PDF/UA
PDF/UA specifies file-level requirements that a PDF must include to support reliable accessibility. In practice, effective access involves the whole chain: the file, the PDF software that processes it, and the assistive technologies that present it to the user.
Elements in a PDF must be identified as either meaningful content or artifacts. Meaningful content, such as headings, paragraphs, tables, images, and bookmarks, must be tagged in a single structure tree that captures the document’s logical reading order. Artifacts, such as decorative lines, background elements, or other non-essential visuals, must be marked as such so that assistive technology can ignore them.
Key file-level requirements include, but are not limited to:
Using standard PDF tags or mapping custom tags to standard ones with a role map
Ensuring the tag structure reflects the document’s logical reading order
Adding alternative text for images and other non-text objects
Setting a title that appears in the document window, not just the file name
Declaring the document’s primary language and marking any language changes
Avoiding color, layout, or position alone to convey meaning
The specifics differ between PDF/UA-1 and PDF/UA-2, but the foundation is the same: a tagged, logically ordered document that compatible PDF software and assistive technologies can interpret.
PDF/UA versions and related standards
The two editions of the PDF/UA standard are based on different underlying PDF specifications, reflecting an evolution in the format.
PDF/UA-1 (ISO 14289-1)
Published in 2012, this version is based on the widely used PDF 1.7 specification. It defined the technical requirements for a logical document structure and described how PDF software and assistive technologies should expose that structure. The standard was then revised in 2014 to include a variety of corrections.
PDF/UA-2 (ISO 14289-2)
This newer version, published in 2024, is a complete rewrite based on the modern PDF 2.0 specification. While its core principles are the same as PDF/UA-1, it introduced significant improvements with more explicit rules for annotations and how structure elements from PDF 1.7 relate to those in PDF 2.0. It also added support for modern Unicode, which improves how text is handled in a broader range of languages.
PDF/UA and WCAG
The Web Content Accessibility Guidelines (WCAG), developed by the W3C, is the international benchmark for digital accessibility. While WCAG guides the creation of accessible content in general, PDF/UA brings those ideas into the world of PDF and sets PDF-specific rules. It provides a means of making PDF files that conform to WCAG.
However, conformity to PDF/UA alone does not guarantee a document’s full accessibility. PDF/UA provides the technical features of an accessible PDF, but it does not address issues related to the content itself.
For instance, document creators must ensure that a PDF has proper color contrast, as PDF/UA cannot fix issues where text is too close in color to its background for users with low vision. Similarly, while PDF/UA ensures content is structured and readable, it cannot fix overly complex or inaccessible content to people with certain cognitive impairments.
The benefits of PDF/UA
PDF/UA’s primary aim is to set precise, testable requirements for accessible PDFs, supporting equal access to information for people with disabilities. However, adhering to this standard also makes a PDF more usable and valuable for everyone involved.
Assistive access and navigation
When a file includes tags for structure and reading order, people using screen readers, Braille displays, or keyboard navigation can move predictably through headings, lists, tables, images, and labeled form fields. This supports efficient reading, section navigation, and completing tasks such as filling out and submitting forms. Declaring the document language improves speech and braille output, while alternative text provides meaningful image descriptions.
Improved readability and searchability
Tagged structure can enable reflow in PDF viewers that support it, making documents easier to read on small screens without horizontal scrolling. The same structural and metadata signals, such as document title, section headings, declared language, and image descriptions, improve machine readability and can help with discovery in search engines.
Organizational value and regulatory compliance
Organizations that invest in producing PDF/UA-conformant documents can broaden their audience and customer reach, demonstrate a commitment to inclusion, and strengthen brand trust and credibility. Crucially, these efforts are increasingly required in public tenders and contracts, set by regulations like the European Accessibility Act and the national laws that implement it across the EU.
The challenges of PDF accessibility in practice
PDF/UA defines what an accessible PDF must include. Applying those requirements across document workflows can be demanding. PDFs originate from different toolchains and pipelines, often at high volume, and the structure needed by assistive technologies is not always preserved. Some of the main challenges include:
User experience barriers
When PDFs lack dependable tags and reading order, assistive technologies cannot predictably present the content. People miss context in tables and forms, or cannot complete tasks. In public and customer-facing situations, this leads to drop-offs, support calls, and complaints, highlighting the need for a planned assessment and remediation approach rather than ad hoc fixes.
Volume and variability
PDFs originate from Office exports, template engines, legacy generators, and scans. Some sources preserve structure; others drop or distort it. High volume and varied templates force decisions about which document types to address first and how to plan quality control.
Compliance expectations and continuity
Regulatory and stakeholder expectations vary by market and evolve over time. Organizations need evidence that files meet accessibility requirements and a repeatable way to keep them accessible as standards and testing guidance progress, while balancing deadlines, risk, and budget.
Final thoughts
While the technical and logistical challenges of PDF compliance are real, the regulatory and ethical imperatives are clear and increasingly mandated. PDF/UA is the standard that translates the goals of WCAG into a technical reality. For organizations, this means treating PDF accessibility not as a final audit step, but as a core requirement of digital governance, requiring dedicated effort to ensure that content is not only compliant but truly inclusive.
How Pdftools supports PDF/UA compliance
As software providers with deep expertise in PDF core technology, we understand the technical demands of this challenge. We recognize that PDF/UA compliance requires sophisticated tooling to manage document structure and integrity. Our products, including the Pdftools SDK and Conversion Service, are engineered as foundational components for high-volume environments, supporting integration into existing systems for two crucial areas: programmatic creation and structural modification of PDF files, and auditable PDF/UA validation and checking at scale.