Overview of the PDF/UA Standard

PDF/UA is the international standard that defines what it means for a PDF document to be accessible. It establishes clear technical and structural requirements so that PDF content can be reliably used with assistive technologies such as screen readers.

This overview explains what PDF/UA is, how it relates to WCAG, and why it is central to accessible PDF compliance.

What is PDF/UA?

PDF/UA stands for PDF/Universal Accessibility. It is published as ISO 14289 and is the only formal, file-format–specific accessibility standard for PDFs.

While WCAG defines accessibility requirements at a content level, PDF/UA defines how those requirements must be implemented inside a PDF file.

In other words:

• WCAG explains what accessibility requires

• PDF/UA explains how a PDF must be built to meet those requirements

Why PDF/UA exists

PDF files are complex documents that combine content, structure, layout, and interactivity. Without a strict technical standard, PDFs can appear accessible visually while remaining unusable for assistive technology users.

PDF/UA exists to:

• Ensure consistent document structure

• Enable reliable navigation for screen readers

• Define how tags, metadata, and reading order must be implemented

• Remove ambiguity from accessibility evaluations

It provides a common benchmark for organizations, vendors, and auditors.

How PDF/UA relates to WCAG

PDF/UA does not replace WCAG. It supports it.

WCAG success criteria apply to PDFs, but WCAG alone does not specify:

• How tags must be structured

• How reading order must be encoded

• How metadata must be defined in PDF files

PDF/UA fills this gap by mapping WCAG requirements to PDF-specific technical rules.

In accessibility workflows, PDFs are typically evaluated against:

• WCAG for content requirements

• PDF/UA for file-format implementation

What PDF/UA requires

PDF/UA defines mandatory requirements for accessible PDFs, including:

• A complete and logical tag structure

• Correct reading order

• Proper use of headings, lists, and tables

• Defined document language

• Meaningful alternative text for images

• Accessible forms and annotations

• Removal or hiding of decorative elements

If any required element is missing or incorrect, the PDF fails PDF/UA compliance.

How PDF/UA compliance is tested

PDF/UA compliance is typically evaluated using a combination of:

• Automated technical validation (such as PAC testing)

• Manual inspection of structure and semantics

• Assistive technology testing

Automated tools can detect many technical failures, but manual review is required to confirm meaning, usability, and intent.

When PDF/UA compliance is required

PDF/UA is commonly required or expected when PDFs are:

• Published by public sector organizations

• Distributed to customers or the public

• Submitted for procurement or tendering

• Used in regulated or audited environments

Many accessibility policies reference WCAG, but PDF/UA is often the practical standard used to verify compliance for PDFs.

Conclusion

PDF/UA provides a clear, enforceable definition of accessible PDF documents. It removes ambiguity from accessibility testing and ensures that PDFs can be reliably used with assistive technologies.

Organizations that publish PDFs at scale or in regulated contexts should understand PDF/UA and ensure their documents are evaluated against its requirements.

Accessibility Testing Note

PDF/UA compliance is typically verified during formal accessibility testing alongside WCAG evaluation, especially for documents intended for public or regulated use.