PDF/UA is the international standard for accessible PDF, published as ISO 14289 in two parts. Part 1 covers files built on PDF 1.7 and part 2 covers PDF 2.0. They are siblings rather than successive versions, so which one applies depends on the version of PDF you are producing. It describes the finished file rather than the way you make it. What has to be tagged, how the tag tree is structured, what metadata has to be there. It says nothing about how to produce one. Its custodian is clear about something else, too. Conforming to it does not by itself make a document accessible. It has a colour checkpoint and it asks only that meaning carried by colour also lives in the tags, so there is no contrast ratio to measure anywhere in it. It has scripting checks and they cover particular behaviours rather than whether your interactive form can be used. And whether the words can be understood is outside it entirely. Those are the parts WCAG covers, which is why the two are companions and why laws name WCAG.
In practice
PDF/UA is precise where WCAG is outcome-based. Every meaningful element tagged, a tag tree that reflects the logical structure, artifacts of layout marked as artifacts, and metadata including a title and a language. There is a free enumeration of every way to fail part 1, called the Matterhorn Protocol, which runs to 31 checkpoints and 136 failure conditions and works as an audit checklist as it stands. Roughly two thirds of those conditions can be settled by software and the rest need a person. Be careful quoting an exact split, because more than one has been published and they do not agree. That balance is also why a PDF report looks nothing like a web accessibility report.
Part 1 of the standard is free. The PDF Association hosts it at no cost, so anybody arguing about what PDF/UA-1 actually requires can go and read it. Two practical decisions come out of the same place. A file can carry a machine-readable WCAG conformance claim in its own metadata, which is worth having if you publish documents at any scale. And if you also archive under PDF/A, pick part 2 or part 3, because combining PDF/UA with the first part of PDF/A is specifically not recommended.
Laws name WCAG, and the way WCAG reaches a document is worth knowing. Under the US Section 508 standards, electronic content has to meet WCAG 2.0 at Levels A and AA, with the word document substituted wherever the criteria say web page. WCAG also carries its own PDF techniques, which is why a form field inside a PDF has a name, role and value obligation with W3C techniques written for meeting it.
Why it matters
Aim at the WCAG level your obligation names, and use PDF/UA as the specification for how to build the file so it gets there. They point the same direction and they are not interchangeable. The trap is treating PDF/UA as a finish line. A document can pass every check it sets and still have grey text on a white background, because nothing in it measures a contrast ratio. It can carry a script producing something nobody can reach, because its scripting checks cover flickering, an unaccompanied beep and keystroke timing rather than whether the thing works. And prose that defeats the reader it was written for is outside it altogether. Those are real findings and they belong to WCAG.
Does my PDF need a skip link
No. Under the US Section 508 standards a non-web document is excused from four WCAG criteria, and bypass blocks is one of them, alongside multiple ways, consistent navigation and consistent identification. Everything else at Levels A and AA still applies to the file.
Where this shows up on the site
Related terms
- Tagged PDFA tagged PDF carries an invisible structure layer naming each part of the document.
- WCAG2ICTWCAG2ICT explains how to apply WCAG to things that are not web pages.
- ConformanceConformance means satisfying all the requirements of a standard, and WCAG has five of them rather than one.
- WCAGWCAG is the international standard for web accessibility, published by the W3C.
- Accessibility treeThe accessibility tree is a second structure the browser builds alongside the DOM, holding one object for every part of your page that has to be exposed to assistive technology.
Knowing the word is the easy part.
Find out where your own site stands. The free scan checks 10 pages in a real browser against all 90 supported automated rules, separates 27 best-practice checks from its WCAG findings, and names the rule behind every result.