UA1 Validator / PDF/UA-1 rules / 7.4.4-3

PDF/UA-1 · CLAUSE 7.4.4

Heading structure is inconsistent

The document mixes strongly structured headings (H1, H2, H3) with weakly structured H tags, skips heading levels, or nests more than one H under a single node.

Rule 7.4.4-3 ISO 14289-1 Object: SEHn

Why it matters

Heading navigation is the primary way screen reader users skim a document. Skipped or inconsistent levels break the outline they navigate by.

How to fix it

  • Pick one model: numbered headings (H1..H6) throughout, or H tags throughout, never both in the same file.
  • Start at H1 and do not skip levels when descending (H1 > H2 > H3).
  • Fix heading levels in the source document's paragraph styles so every export is correct.
WCAG 1.3.1 Info and Relationships (A) WCAG 2.4.6 Headings and Labels (AA)

What the standard says

All documents shall be either strongly or weakly structured, but not both

Check your own PDF

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curl -sS -X POST "https://api.ua1.dev/api/validate?format=compact&profile=ua1" \
  -F "file=@document.pdf"