By PDFKits Team — Published February 19, 2026
Accessibility in digital documents is not merely a legal requirement; it is a fundamental commitment to ensuring that every person, regardless of ability, can access and understand the information you share. The Portable Document Format has become the global standard for distributing official documents, contracts, reports, and educational materials. Yet a staggering number of PDFs published online remain inaccessible to people who rely on assistive technologies such as screen readers, magnifiers, and alternative input devices.
According to the World Health Organization, over one billion people worldwide live with some form of disability. When a PDF document lacks proper structure, alternative text for images, or logical reading order, it becomes an impenetrable barrier for a significant portion of the population. Government agencies, educational institutions, healthcare organizations, and businesses all share a responsibility to produce documents that everyone can consume.
The Web Content Accessibility Guidelines (WCAG) 2.1, published by the World Wide Web Consortium (W3C), provide the internationally recognized framework for digital accessibility. While originally designed for web content, WCAG principles apply directly to PDF documents. Compliance with WCAG 2.1 at the AA level is required by legislation in many countries, including the Americans with Disabilities Act (ADA) in the United States, the Accessibility for Ontarians with Disabilities Act (AODA) in Canada, and the European Accessibility Act in the European Union. Using PDFKits and its 24+ free tools, you can take meaningful steps toward making your PDF documents accessible without installing expensive desktop software.
WCAG 2.1 is built around four core principles, often abbreviated as POUR: Perceivable, Operable, Understandable, and Robust. Each principle contains specific guidelines and success criteria that define what constitutes accessible content. For PDF documents, these principles translate into concrete technical requirements that authors and editors must address.
The perceivable principle requires that information and user interface components be presentable to users in ways they can perceive. For PDFs, this means providing text alternatives for non-text content such as images, charts, and diagrams. Every informative image in a PDF must include alternative text (alt text) that conveys the same information as the visual element. Decorative images should be marked as artifacts so that screen readers skip them entirely. Color must not be the sole means of conveying information; for example, a chart that uses only color to distinguish data series must also use patterns, labels, or other visual cues. Text must have sufficient contrast against its background, with a minimum contrast ratio of 4.5:1 for normal text and 3:1 for large text at WCAG AA level.
Many users with motor disabilities navigate documents using a keyboard or other alternative input devices rather than a mouse. An accessible PDF must support keyboard navigation through all interactive elements, including form fields, links, and bookmarks. The reading order and tab order must be logical, following the visual flow of the document. Interactive form fields must be properly labeled so that users can identify their purpose without relying on visual positioning. Bookmarks should be provided for documents longer than a few pages to facilitate efficient navigation. The Edit PDF tool can help you add and organize interactive elements within your documents.
The understandable principle requires that content and interface operation be comprehensible. For PDF documents, this means specifying the document language so that screen readers use the correct pronunciation rules. Complex documents should use headings, lists, and tables with proper structural markup rather than relying solely on visual formatting. Instructions should not depend on sensory characteristics alone, such as telling users to click the red button or refer to the image on the right. Consistent navigation aids such as headers, footers, and page numbers help users orient themselves within longer documents.
Robust content is content that can be reliably interpreted by a wide variety of user agents, including assistive technologies. For PDFs, robustness is primarily achieved through proper tagging. Tagged PDFs contain a logical structure tree that maps the visual content to semantic elements such as headings, paragraphs, lists, tables, and figures. This structure tree is what assistive technologies use to present the content meaningfully. Without tags, a screen reader may read content in the wrong order, miss important structural relationships, or present tables as unstructured blocks of text. The W3C Web Accessibility Initiative provides detailed technical documentation on implementing these principles.
A tagged PDF is a PDF document that contains an internal structure tree defining the logical organization of the content. Tags identify elements such as headings (H1 through H6), paragraphs (P), lists (L, LI, Lbl, LBody), tables (Table, TR, TH, TD), figures (Figure), and links (Link). This structure tree is independent of the visual layout and serves as the blueprint that assistive technologies use to interpret the document.
Without tags, a PDF is essentially a collection of visual elements positioned on a canvas. A screen reader encountering an untagged PDF must guess the reading order based on the coordinates of text blocks, which frequently produces incorrect results, especially in multi-column layouts, documents with sidebars, or pages with complex visual designs. Tables in untagged PDFs are particularly problematic because the screen reader cannot determine which cells belong to which rows and columns, rendering tabular data incomprehensible to users who cannot see the visual layout.
The most effective way to create a tagged PDF is to start with a well-structured source document. If you are working in Microsoft Word, use the built-in heading styles (Heading 1, Heading 2, Heading 3) rather than manually formatting text to look like headings. Use the list tools to create bulleted and numbered lists rather than typing dashes or numbers manually. Insert images using the proper image insertion tools and add alt text through the image properties dialog. When you export to PDF, select the option to create a tagged PDF. Similar principles apply in Google Docs, LibreOffice, and other word processors. If you need to create a PDF from scratch, the Create PDF tool can help you build structured documents directly in your browser.
Many existing PDFs lack proper tags or have incorrect tagging. Adobe Acrobat Pro includes an accessibility checker and tag editing tools, but not everyone has access to this expensive software. Free alternatives exist for checking tag structure, including the PAC (PDF Accessibility Checker) tool developed by the Swiss foundation Access for All. When repairing tags, focus first on the document's heading structure, then address reading order issues, and finally ensure that all images have appropriate alt text. Tables should be checked to verify that header cells are marked with TH tags and that the scope attribute correctly identifies whether headers apply to rows or columns.
Alternative text is a textual description of non-text content that conveys the same information or function as the visual element. Writing effective alt text is both an art and a science, and it requires understanding the context in which the image appears within the document.
Effective alt text should be concise yet descriptive, typically ranging from a few words to one or two sentences. It should convey the purpose and content of the image, not merely describe its visual appearance. For example, a chart showing quarterly revenue growth should have alt text that summarizes the key data points and trends, not simply state that the image is a bar chart. An organizational chart should describe the hierarchical relationships it depicts. A photograph used to illustrate a concept should describe the relevant aspects of the image that relate to the surrounding text.
Not every image in a document requires alt text. Decorative images that serve no informational purpose, such as borders, dividers, or background patterns, should be marked as artifacts in the PDF tag structure. This tells screen readers to ignore them entirely, reducing clutter in the audio presentation. However, be cautious about classifying images as decorative. If an image contributes to understanding the content in any way, it is informative and requires alt text. When in doubt, provide alt text.
Some images are too complex to describe adequately in a short alt text string. Detailed diagrams, data visualizations, infographics, and maps may require a long description that provides all the information contained in the image. In HTML, this can be accomplished using the longdesc attribute or an adjacent text description. In PDFs, you can provide a detailed description in the tag's ActualText or Alt property, or you can include a text-based equivalent of the information adjacent to the image in the document flow. For charts and graphs, consider including a data table that presents the same information in a format that is inherently accessible to screen readers.
The reading order of a PDF determines the sequence in which a screen reader presents the content to the user. In a properly structured document, the reading order follows the logical flow of the content, which may differ from the visual layout. For example, a two-column document should be read from top to bottom of the first column, then from top to bottom of the second column, not from left to right across both columns simultaneously.
The reading order in a tagged PDF is determined by the order of elements in the structure tree, not by their physical position on the page. When creating documents, ensure that the structure tree reflects the intended reading sequence. If you are working with a document that has an incorrect reading order, you will need to reorder the tags in the structure tree. This can be done using tag editing tools in PDF editors. Pay particular attention to headers, footers, sidebars, callout boxes, and footnotes, as these elements are frequently misplaced in the reading order.
Multi-column layouts present special challenges for accessibility. While visually appealing, they can confuse assistive technologies if the underlying structure does not clearly define the column boundaries. When a document uses columns, the tag structure must group content by column so that the screen reader presents all content in the first column before moving to the second. This is especially important in academic papers, newsletters, and brochures where multi-column layouts are common.
Repeated elements such as headers, footers, and page numbers should be marked as artifacts in the PDF tag structure. This prevents screen readers from announcing these elements on every page, which would be extremely disruptive to the reading experience. The Page Numbers tool can add visual page numbers to your documents while maintaining proper document structure. With the 24+ tools available on PDFKits, you can handle both the visual formatting and structural requirements of accessible documents.
PDF forms present unique accessibility challenges because they combine visual layout with interactive functionality. An accessible PDF form must be usable by people who cannot see the visual layout and who navigate using a keyboard or other alternative input device.
Every form field must have a descriptive label that is programmatically associated with the field. A sighted user can determine the purpose of a form field by reading the nearby text label, but a screen reader user depends on the programmatic association between the label and the field. If a form field lacks a proper label, the screen reader may announce it as simply text field or checkbox, providing no indication of what information the user should enter. Properly labeled fields announce themselves as, for example, First Name, edit text or I agree to the terms of service, checkbox not checked.
Users who cannot use a mouse navigate PDF forms using the Tab key to move between fields. The tab order must follow the logical sequence of the form, typically moving from top to bottom and left to right. If the tab order does not match the visual layout, users may fill in fields out of sequence or miss required fields entirely. Testing the tab order by navigating the form with only a keyboard is an essential step in ensuring form accessibility.
Accessible forms should provide clear instructions at the beginning of the form explaining how to complete it. Required fields should be identified in a way that does not rely solely on color (such as a red asterisk). Error messages should be descriptive and help the user understand what needs to be corrected. For example, rather than simply indicating that a field has an error, the message should state something like Please enter a valid email address in the format name@example.com.
Creating an accessible PDF is only half the process; testing is equally important. Accessibility testing should combine automated checking with manual verification using assistive technologies.
Several tools can automatically check PDF documents for common accessibility issues. Adobe Acrobat Pro includes a built-in accessibility checker that evaluates documents against a set of rules. The PAC (PDF Accessibility Checker) is a free tool that provides detailed reports on accessibility conformance. These automated tools can identify missing alt text, improper heading structure, missing form labels, insufficient color contrast, and other technical issues. However, automated checkers cannot evaluate the quality of alt text or the logical correctness of reading order, which requires human judgment.
The most definitive test of PDF accessibility is to open the document with a screen reader and listen to how it is presented. NVDA (NonVisual Desktop Access) is a free, open-source screen reader for Windows that supports PDF documents. JAWS (Job Access With Speech) is a commercial screen reader widely used in professional environments. VoiceOver is built into macOS and iOS devices. Testing with at least one screen reader helps identify issues that automated checkers miss, such as confusing reading order, unhelpful alt text, or form fields that are difficult to navigate. Using PDFKits and its 24+ free tools alongside screen reader testing creates a comprehensive workflow for producing accessible documents.
Text in PDF documents must meet minimum contrast ratios to be readable by people with low vision or color vision deficiencies. The WCAG 2.1 AA standard requires a contrast ratio of at least 4.5:1 for normal text and 3:1 for large text (18 points or larger, or 14 points bold). Free online contrast checkers can verify whether specific color combinations meet these thresholds. When creating documents, choose color schemes that provide sufficient contrast and avoid using light gray text on white backgrounds, which is a common accessibility failure.
A tagged PDF contains an internal structure tree that defines the logical organization of the document, including headings, paragraphs, lists, tables, and images. This structure tree is essential for assistive technologies like screen readers to present the content in a meaningful order and format. Without tags, a screen reader may read content out of order or miss important structural relationships.
In many jurisdictions, yes. The Americans with Disabilities Act (ADA) in the United States, the European Accessibility Act in the EU, and similar legislation in other countries require that digital documents, including PDFs, be accessible to people with disabilities. Government agencies and organizations receiving public funding typically face the strictest requirements, but private businesses are increasingly subject to accessibility mandates as well.
Alt text can be added during document creation in word processors like Microsoft Word or Google Docs by right-clicking an image and selecting the alt text option. For existing PDFs, you can use PDF editing software to select each image and add alt text through the tag properties. The alt text should describe the content and purpose of the image concisely.
Scanned PDFs are image-based and contain no actual text, making them inherently inaccessible. The first step is to run OCR (Optical Character Recognition) to convert the scanned images into searchable text. After OCR processing, the document needs proper tagging, reading order verification, and alt text for any images. While OCR significantly improves accessibility, the results should be proofread for accuracy.
Free tools include PAC (PDF Accessibility Checker) for comprehensive conformance reports and NVDA screen reader for real-world testing. Adobe Acrobat Pro includes a built-in accessibility checker. Online contrast checkers can verify color combinations. Combining automated checking with manual screen reader testing provides the most thorough assessment of document accessibility.