PDF Accessibility: How to Make PDFs Actually Readable by Everyone

An inaccessible PDF is one that a screen reader can't navigate, a keyboard user can't interact with, or someone with low vision can't read. The majority of PDFs on the web fail at least one of these. Making a PDF accessible isn't complicated — most of the work happens at creation time, not after.

Tagged PDFs vs untagged PDFs

A tagged PDF includes structural information: headings, paragraphs, lists, tables, image descriptions. This is what screen readers use to understand and navigate the document. An untagged PDF is just a visual layout — the screen reader can't tell a heading from a paragraph. If you export from Word or InDesign, tagged output is usually an option in the PDF settings. Use it.

Reading order matters

Visual order and reading order aren't always the same. A two-column layout that looks obvious to a sighted reader can be read in the wrong sequence by a screen reader (right column first, then left column, for example). Always check the reading order in your PDF's tag tree, not just how it looks visually.

Every image needs alt text

Meaningful images need alternative text that conveys the information. Decorative images should be marked as artifacts (meaning 'ignore this'). The most common failure: charts, graphs, and infographics with no alt text. If the chart shows quarterly revenue growth, the alt text should convey the key takeaway, not just say 'chart'.

Accessible PDF forms

PDF form fields need explicit labels, correct tab order, and error messages that don't rely solely on color. Test your form by tabbing through it with a keyboard — you should always know where you are and what each field is for.

Color contrast

Text should meet WCAG contrast ratios: 4.5:1 for normal text, 3:1 for large text. This matters for users with low vision. A light gray text on white background that looks fine in a design mockup often fails contrast requirements.

How to test accessibility

Adobe Acrobat Pro has a built-in accessibility checker. PAC 3 (PDF Accessibility Checker) is free and gives detailed results. For a quick test, try reading your PDF with a screen reader (NVDA on Windows is free) — this reveals navigation issues that automated checkers miss.