How to check if a PDF is accessible

Most PDFs that look fine are not accessible. You can't tell by looking at them. The only way to know is to check what is inside the file.

Here is the short version. Start with a few quick tests: can you select the text, does the file have tags, does it have a real title and language, and does it read in the right order. Then run an automated checker. Finish with a manual review, because automated tools only catch part of the problem.

When we started working with county documents, the first question we heard was always the same: how do we even know if a file is accessible? This post walks through how to find out.

A PDF can look perfect on screen and still be unusable with a screen reader. Accessibility lives in the file's structure: the text layer, the tags that mark headings and tables, the reading order, and descriptions for images.

None of that shows on screen. Two PDFs can look identical while one works for a blind reader and the other says nothing at all.

• Try to select the text. Click and drag across a paragraph. If you can't highlight individual words, the page is an image, usually a scan.
• Copy and paste a paragraph. Paste it into a plain text editor like Notepad. If you get gibberish, missing letters or random symbols, the text layer is broken. This happens with poor text recognition or fonts that don't map to real characters. A screen reader reads exactly what you pasted.
• Search for a word. Press Ctrl+F (Cmd+F on a Mac) and search for a word you can see. If search finds nothing, a screen reader will find nothing too.
• Check the document properties. Open File, then Properties. Look for a real title, not a file name like "Scan_0042", and check that the language is set.
• Look for tags. Many PDF readers show "Tagged PDF: Yes" or "No" in the document properties. No tags means a screen reader has no structure to follow

Scanned files fail the first check almost every time.

An automated checker tests the file against the standards, WCAG 2.1 AA and PDF/UA. It is fast and consistent, and it is the best way to check many files at once. It flags things like:

• Missing tags
• No document title or language
• Images with no alt text
• Tables without header cells
• Fonts that are not embedded properly
• Form fields with no label

You can try this on your own file with our free accessibility checker.

A checker can tell you an image has alt text. It can't tell you whether that alt text makes sense. The same goes for reading order, headings and tables. These need a person.

• Alt text quality. "image1" passes some checks but helps no one.
• Reading order. A checker confirms an order exists, not that it is right. Two-column pages and sidebars often read in the wrong sequence.
• Headings. Is there a logical heading structure, or is everything tagged as body text that just looks bold?
• Tables. Are header cells linked to the right data? Complex tables often aren't.
• Form fields. Does each label actually describe what the field asks for?

That is why a passing result is a starting point, not a final answer.

The most honest test is to hear the document. NVDA is free on Windows, and VoiceOver is built into Macs. Open the PDF, look away from the screen, and listen to a page.

Does it make sense in the order you hear it? Can you tell what each table column means? Are images described? If the answer to any of these is no, the document isn't accessible yet, whatever the checker says.

• Start with your most-used documents: forms, applications and current notices.
• Run the quick checks and separate scanned files from born-digital ones. Scans need the most work.
• Run an automated checker on everything.
• Review anything that passes for alt text, reading order, headings and tables.
• Spot-check a few files with a screen reader.
• Keep a simple log of what passed, what failed and what was fixed.

The log matters more than it looks. If someone raises a complaint, it shows what you checked and when.