PDF/UA vs WCAG: what’s the difference?

WCAG in one paragraph

The Web Content Accessibility Guidelines 2.1 are success criteria for any web content — pages, apps and documents. They describe outcomes (“information and relationships conveyed through presentation can be programmatically determined”) rather than file formats. The W3C publishes PDF techniques that show how to meet the criteria in a PDF.

PDF/UA in one paragraph

PDF/UA (“Universal Accessibility”) is ISO 14289. Part 1 (2014) applies to PDF 1.7; part 2 (PDF/UA-2) applies to PDF 2.0. It specifies how tags, structure, fonts, metadata and annotations must be encoded so assistive technology can use the file reliably. The PDF Association’s Matterhorn Protocol 1.1 lists “31 checkpoints comprised of 136 failure conditions… 87 failure conditions can be determined by software alone, 47 failure conditions usually require human judgment.” Validators such as veraPDF and PAC check against it.

Side-by-side

The two don’t map one-to-one: a PDF/UA-valid file can still fail WCAG on contrast or meaningful alt text, and WCAG alone doesn’t pin down PDF internals (PDF Association talk).

Which one do you need?

For legal compliance under ADA Title II, the target is WCAG 2.1 AA (see the ADA Title II PDF guide). In practice, asking vendors for PDF/UA-validated output plus a WCAG review is the most reliable way to get there. Use the checklist for day-to-day checks and PDF Triage to find which files need work first.

Frequently asked questions