A tag describes what content is, not how it looks. Large text is not always a heading. A box is not automatically a table. The names below are case-sensitive technical names. Our example trees explain structure; they are not code to paste into a PDF.
The reference becomes useful when you know what each tag should represent. Start with the page: is the content a section heading, a paragraph, a list item or a table cell? Then inspect both the structural type and the content associated with it.
A Table whose children are all P does not describe cell relationships merely because its outer container is called a table. A typical row structure needs TR and cells represented by TH or TD. Similarly, L alone does not make a well-formed list when its items are misplaced. The container contributes meaning; its internal relationships make that meaning usable.
The tag tree is not a map of page coordinates. A paragraph can continue across a page break. A heading wrapping onto two lines remains one heading. Avoid creating separate content elements for each line or page when this splits a continuous thought.
| Tag | Purpose in brief |
|---|---|
| Document | The document’s overall structure. |
| Part, Art, Sect | Part, article and section; choose according to the organisation of the content. |
| Div, NonStruct | Grouping; do not replace a more meaningful tag with these. |
| BlockQuote | A quotation presented as a separate block. |
| Caption | A figure, table or list caption. |
| TOC, TOCI | A table of contents and one of its entries. |
| Index | An index. |
| Private | Application-specific private content; not a shortcut for hiding information readers need. |
| Tag | Purpose in brief |
|---|---|
| P | Paragraph. |
| H, H1–H6 | Heading; numbered types give an explicit level in PDF 1.7. |
| L, LI | List and list item. |
| Lbl, LBody | A label or number and the item’s body. |
| Span | A text portion without a distinct structural meaning of its own. |
| Quote, Note | Inline quotation and note. |
| Reference, BibEntry | A reference and a bibliographic entry. |
| Code | Computer code. |
Sources: [1]
| Tag | Purpose in brief |
|---|---|
| Table, TR | Table and row. |
| TH, TD | Header cell and data cell. |
| THead, TBody, TFoot | Row groups: header, body and footer. |
| Figure | An image or other graphical information. |
| Formula | Mathematical formula. |
| Link | Link structure; its connection to the link annotation also needs to work. |
| Annot | Another annotation represented in the structure. |
| Form | Interactive form field; labels, properties and keyboard use also need checking. |
Ruby represents pronunciation or other annotations associated with base text. Warichu supports particular inline commentary in East Asian typography. These are distinct text structures, not general-purpose footnote mechanisms.
| Tag | Part |
|---|---|
| Ruby, RB, RT, RP | Whole, base text, annotation text and delimiters. |
| Warichu, WT, WP | Whole, text and delimiters. |
Sources: [1]
PDF 2.0 adds Title, FENote, Aside, DocumentFragment, Em, Strong, Sub and the Artifact structure type. Numbered headings can go beyond H6. Sub means a subdivision of a block, not automatically subscript text.
Art, BlockQuote, BibEntry, Code, Index, Note, Private, Quote, Reference, TOC and TOCI are not in the PDF 2.0 standard namespace. Their names are not thereby banned from every PDF 2.0 file: namespaces and any role mapping need assessment. The meaning of some shared names has also changed.
In PDF 1.7, artifacts are specially marked page content, not a standard structure type in the tag tree. PDF 2.0 also has a structure type named Artifact. Do not confuse the mechanisms when repairing or validating a file.
A boxed passage is not automatically a table. If it contains a heading and two paragraphs, those are the meanings to represent. A table is appropriate when information has relationships in both rows and columns. Do not use Table merely because the authoring tool used a table for layout.
A quotation needs distinguishing from ordinary text where the distinction carries meaning, but an arbitrary italic word is not consequently a block quotation. Choose a type appropriate to the PDF version and namespace; the PDF 1.7 reference cannot be applied unchanged to every PDF 2.0 file.
A note needs meaningful content and a usable connection between its reference and text where navigation is needed. Renaming P to Note or FENote does not create the complete relationship. Check that the note does not interrupt the main text mid-sentence.
A Formula represents a mathematical expression, not merely an image of unusual characters. Its representation and delivery depend on the target standard and tool support. A simple spoken substitute can help in some contexts, but is not a universal solution for mathematics.
Sources
- Tagged PDF Best Practice Guide: SyntaxPDF Association
- Well-Tagged PDF 1.0PDF Association
- PDF10: Labels for interactive form controlsW3C
- PDF12: Name, role and value for form fieldsW3C
Examples are our own unless stated otherwise. These guides distinguish legal requirements, standards and practical advice. Passing an automated check is not a complete assessment of document accessibility.