Tagged PDF (tag structure)

A tagged PDF carries a structure tree that lets screen readers recognise headings, lists and tables.

What is a tagged PDF?

A tagged PDF contains a logical structure, the tag or structure tree, in addition to the visible page image. Each tag assigns a role to a piece of content, for example heading, paragraph, list, table or figure. Assistive technologies read this structure and present it in a different form.

WCAG 2.1 describes the purpose. Under Success Criterion 1.3.1 "Info and Relationships" (Level A), information, structure and relationships conveyed through presentation must be programmatically determined or available in text. According to the WCAG glossary, "programmatically determined" means that software determines the information from author-supplied data in a way that user agents, including assistive technologies, can extract and present it in different modalities. The glossary names screen readers as an example of assistive technology, which blind people use to read text through synthesised speech or braille. WCAG expressly lists PDF as an example of a web content technology.

If a heading is recognisable only through font size or bold type, the structure is conveyed by presentation alone. This is exactly the case criterion 1.3.1 addresses. Tags make the organisation of the document readable for software. For the standard on accessible PDF files, see the glossary entry PDF/UA.

Standards: EN 301 549, WCAG 2.1 and PDF/UA

Neither EN 301 549 V3.2.1 nor WCAG 2.1 uses the expression "tagged PDF". Both are worded in terms of results: In clause 10, EN 301 549 adopts WCAG 2.1 success criteria for documents, some with adapted wording, while some clauses are marked as void. Criterion 1.3.1 is adopted in clause 10.1.3.1.

• EN 301 549, clause 3.1: A non-web document is a document that is not a web page, not embedded in web pages nor used in the rendering or functioning of the page.
• EN 301 549, clause 10.0 (informative): Clause 10 applies to documents that are not web pages, to documents that are not embedded in web pages, and to documents that are provided with web pages but are neither embedded nor rendered together with the web page. This covers downloadable documents. Clause 9 applies to documents that are embedded in web pages and rendered together with them.
• EN 301 549, clause 10.1.3.1: A non-web document shall satisfy WCAG 2.1 Success Criterion 1.3.1. The note describes it as best practice to map non-standard structure types (roles) to a standard structure type as a fall-back solution.
• EN 301 549, clause 10.1.3.2: Criterion 1.3.2 "Meaningful Sequence" applies as well, see reading order.
• EN 301 549, Annex C.10.1.3.1: The type of assessment is inspection. The document passes if it does not fail criterion 1.3.1.
• EN 301 549, clause 4.2.1 note 1: A web page or application with a well formed semantic structure can allow users without vision to identify, navigate and interact with a visual user interface.
• ISO 14289-1:2014 (PDF/UA-1): The International Standard specifies the use of ISO 32000-1:2008 to produce accessible electronic documents. Edition 2 was published in December 2014 and confirmed in 2025. It does not cover specific processes for converting paper or electronic documents to the PDF/UA format.

How laws in Germany and in Austria link to harmonised standards is explained in the entry EN 301 549 and the article PDF/UA, WCAG 2.1 and EN 301 549. The individual success criteria are described in the entry WCAG 2.1.

Practical example

A company provides an annual report created in Word and a training presentation created in PowerPoint as PDF downloads. Both files are downloadable documents within the meaning of clause 10.0 of EN 301 549. Proceed as follows:

1. Build the structure in the source document: styles for headings, real lists and tables with header rows instead of spaces and tabs.
2. Export with tags and then check the tag tree. Do heading levels, lists and table headers match the visible organisation?
3. Map non-standard structure types (roles) to standard structure types. The note to clause 10.1.3.1 recommends this as best practice.
4. Compare the order of the tags with the visible reading order (clause 10.1.3.2).

A tag tree on its own does not demonstrate conformity. Annex C provides for an inspection of the document for clause 10.1.3.1. Step-by-step help is available in the checklist for Word and PowerPoint. If you prefer not to convert reports, forms or presentations yourself, you can have accessible documents prepared.

See also

• PDF/UA (ISO 14289)
• Reading order
• EN 301 549 (harmonised standard for ICT accessibility)
• WCAG 2.1 (Web Content Accessibility Guidelines)