How to Test PDF Accessibility – Free Online Checker & Steps

Creating a PDF is easy, but making sure it’s accessible is where the real challenge lies. Many PDFs look fine visually but are difficult or even impossible to navigate with assistive technologies. That’s why a PDF accessibility test is essential.

In this section, we’ll look at simple manual checks anyone can do, along with specialised tools that highlight accessibility issues and suggest fixes. Together, these techniques give you a clear picture of how accessible your PDF really is.

How to test a PDF for accessibility

To test a PDF for accessibility, start with an automated check, then confirm the rest by hand. An automated checker catches the machine-verifiable problems in seconds, and the six manual checks below cover what a tool can’t judge: keyboard navigation, reading order, color reliance, color contrast, image descriptions, and metadata.

Start with an automated check

Begin by running the PDF through an automated checker. Upload the file to the free online PDF accessibility checker, and in seconds it tells you whether the file is tagged and which machine-verifiable issues it has. Everything is ranked worst-first, so you immediately know where to focus.

One result is worth acting on before anything else: an untagged PDF, which is inaccessible no matter how clean it looks. If the report flags that, fix the tagging at the source before going further, because the rest of the checks have nothing to work with.

The automated pass gives you the map. What it can’t judge is whether the document actually works for a human: whether the reading order makes sense, whether the alt text is meaningful, and whether someone using a screen reader can get through it. That’s what the manual checks below are for.

1. The keyboard navigation test

What you’re testing: Can people move through your PDF using only a keyboard?

Why this matters: Many people with disabilities rely on the keyboard instead of a mouse to read and interact with documents. If your PDF doesn’t support keyboard navigation, you’re putting up unnecessary barriers that prevent them from accessing your content.

What causes this: Keyboard issues usually occur when the PDF isn’t properly tagged or when no tab order is set. Without that structure, the focus can jump around, skip elements, or get stuck, making the document frustrating or even impossible to use.

How to Test It	What to Look For	Red Flags
Open your PDF and set the mouse aside. Use only the keyboard: – Tab to move forward through interactive elements – Shift + Tab to move backwards – Enter to activate links or buttons	– You can reach every link, button, and form field. – The tab order flows logically and predictably. – You can move through the document without getting stuck.	– Some elements can’t be reached at all. – Tab order jumps around in a confusing way. – The focus gets trapped in one section.

2. The reading order test

What you’re testing: Does the screen reader read the PDF in the right order?

Why this matters: A clear reading order is essential for people using screen readers. Otherwise, they will hear content out of sequence, making the document confusing or unusable.

What causes this: Reading order problems usually happen when content is arranged visually but not structurally. Without proper tagging, screen readers follow the order in which elements were added, not how they appear on the page. Images without alt text also leave big gaps in meaning.

How to Test It	What to Look For	Red Flags
In Adobe Acrobat: – Go to View > Read Out Loud > Activate Read Out Loud – Then choose Read This Page Only	– Text flows in a logical order. – Images are announced with clear, meaningful descriptions. – Reading order matches how the content appears on the page.	– Content jumps around or reads out of sequence. – Images are read as “image” or by filename. – Sidebars or footers interrupt the main text.

3. The color contrast check

What you’re testing: Does the text have enough contrast with the background to be readable?

Why this matters: Low contrast text is hard to read for everyone, but especially for people with low vision or color blindness. Even if your content passes the color reliance (grayscale) check, poor contrast can still make it inaccessible.

What causes this: Designers often choose light text on light backgrounds (like grey on white) or trendy color combinations that don’t meet accessibility standards.

How to Test It	What to Look For	Red Flags
Use a free color contrast checker	Text/background combinations meet WCAG 2.1 contrast ratios: – Normal text: 4.5:1 minimum – Large text (18pt+): 3:1 minimum	– Text looks “washed out” or hard to read. – Light grey on white, or low-contrast color pairs. – Fails WCAG contrast ratio tests.

4. The color reliance check

What you’re testing: Does your PDF still make sense without color?

Why this matters: If your document relies only on color to communicate meaning, important details can be lost for people with color blindness or those using grayscale mode. This simple check shows whether your content works even without color cues.

What causes this: Color reliance issues happen when visual cues aren’t backed up with text, patterns, or labels. Charts without labels, links styled only by color, and instructions like “see items in red” are common culprits.

How to Test It	What to Look For	Red Flags
Switch your device to grayscale mode: – Windows: Settings > Ease of Access > Color filters > Grayscale – Mac: System Preferences > Accessibility > Display > Grayscale – iOS: Settings > Accessibility > Display & Text Size > Color Filters > Grayscale – Android: Settings > Accessibility > Color correction > Grayscale	– All information is still clear and understandable. – Links stand out from regular text. – Charts and graphs remain readable and distinct.	– Important information disappears or becomes unclear. – Links blend into the surrounding text. – Chart data becomes hard to interpret.

5. The image description check

What you’re testing: Do images have meaningful descriptions that add context?

Why this matters: If an image has no alt text or if the description is vague or misleading, screen readers can’t explain the image properly. This leaves people missing important details, especially when the image conveys information not explained elsewhere in the document.

What causes this: Missing or poor alt text happens when images are inserted without descriptions, or when descriptions are too vague (like “image1.jpg”) or redundant (“logo”).

How to Test It	What to Look For	Red Flags
– Hover over images to see if text appears. – In Adobe Acrobat, use Read Out Loud to hear how images are announced.	– Important images have meaningful descriptions. – Decorative images are marked as decorative, so they’re skipped. – Descriptions give context without being repetitive.	– Hovering shows nothing or only a filename. – Images are announced as “image” or with vague text. – Decorative graphics are read aloud unnecessarily.

6. The metadata check

What you’re testing: Does the PDF have a proper title and the correct language set?

Why this matters: When a PDF opens, screen readers announce the document title first. If it says “Untitled,” users don’t know what file they’re in. Setting the document language ensures screen readers pronounce text correctly.

What causes this: Authors often skip filling in document properties or forget to set the language before exporting the PDF.

How to Test It	What to Look For	Red Flags
In Acrobat: – Go to File > Document properties > Description to check the Title. – Then switch to the Advanced tab to confirm the Language.	– The title field is filled with a clear, meaningful name. – Language is set correctly (e.g., English, French, etc.).	– The title is blank or “Untitled Document.” – Language field not specified.

Best tools for testing PDF accessibility

You don’t have to test everything by hand. The right tool automates the machine-verifiable checks and hands you a report to work from. Most of these validate against PDF/UA (ISO 14289), the accessibility standard for PDFs, and WCAG.

Here are the tools worth knowing, starting with the fastest free option.

1. WebYes free online PDF accessibility checker

Our free online PDF accessibility checker runs entirely in your browser. Upload a PDF up to 50 MB or paste a public PDF link, and it checks the file against the machine-verifiable success criteria in WCAG 2.1 and 2.2 at levels A and AA, plus the machine-checkable requirements in PDF/UA (ISO 14289), with ADA and Section 508 context. There is no download, no sign-up, and no email required, and your file is not stored; it is deleted after the report is generated.

The report ranks issues worst-first, from Critical through High, Medium, and Low, so you know what to deal with before you spend time on anything else. Each issue comes with the pinpointed location, the WCAG or PDF/UA rule it maps to, a plain-language explanation of what is wrong, and guidance on how to fix it. It is the fastest way to see where a PDF stands without installing anything or handing over your details.

2. Adobe Acrobat Pro

Adobe Acrobat Pro is the closest thing to an all-in-one PDF accessibility tool. Its built-in accessibility check (under All Tools > Prepare for accessibility > Check for accessibility) runs a Full Check against common issues. And unlike most checkers, Acrobat also lets you fix what it finds, editing tags, setting reading order, adding alt text, and correcting metadata in the same place.

The catch is cost. Acrobat Pro runs around $19.99/month on an annual plan billed monthly, which works out to roughly $240 a year, or $29.99/month if you want month-to-month with no annual commitment. If you work with PDFs regularly, it earns its price, but it is a lot to pay just to test the occasional file.

3. PAC (PDF Accessibility Checker)

PAC is the free desktop checker most accessibility professionals reach for, and it has been the reference-grade PDF/UA tool since 2010. It validates against PDF/UA and WCAG, previews how a screen reader will interpret the document’s structure, and includes a table inspector for checking header and data-cell relationships. The latest version now adds AI-assisted checks that evaluate semantic structure like headings, paragraphs, and tables, work that used to be strictly manual.

The limitations are worth knowing. PAC is Windows-only, so there is no Mac or browser version, and like most validators, it checks but does not fix; you will still need another tool to make corrections. It is thorough and free, which is why it stays on almost every tester’s shortlist.

4. veraPDF

veraPDF is the open-source, ISO-backed reference validator for PDF/UA, maintained by the Open Preservation Foundation. It implements the full Matterhorn Protocol (31 checkpoints and 136 failure conditions), the checkpoint basis for machine-verifiable PDF/UA testing, so it is about as rigorous as automated PDF/UA validation gets. It runs as a desktop app and a command-line tool, and can output HTML, XML, or JSON, which makes it useful for automating checks in a build pipeline.

The tool is built for thoroughness, not hand-holding. The output is technical and developer-oriented, and like the other validators here, it reports issues rather than fixing them. If you want the authoritative machine-checkable verdict on PDF/UA conformance, this is the tool, but it assumes you are comfortable reading a detailed validation report.

5. axesCheck

axesCheck is a free online PDF checker from axes4, the team behind PAC. It runs in the browser with nothing to install, so it is a quick way to get a PDF/UA and WCAG read on a file from any device, including a Mac. Upload a PDF, and it returns a machine-verifiable check against the same Matterhorn Protocol rules PAC uses.

Because it is automated, it is limited to machine-checkable rules, so it will not tell you whether the reading order actually makes sense or whether alt text is meaningful. Treat it as a fast online second opinion alongside the manual tests, not a full audit on its own.

Whichever tool you pick, remember that automated checkers only cover machine-verifiable issues, so combine them with the manual tests above to catch the problems a scanner can’t see. For a side-by-side view of the wider field, see our comparison of the 7 Best PDF Accessibility Checkers in 2026.

PDF accessibility best practices

It’s always easier to build accessibility in from the start than to fix problems later. When you create PDFs with accessibility in mind, you save time, avoid costly fixes later, and ensure your content is usable by everyone right from the start.

Here are some best practices to follow:

• Ask if it really needs to be a PDF: A PDF is not always the most accessible option. Think about your audience and the content type before defaulting to this format.
• If your PDF is a form: Consider using a web form (such as Google Forms or Qualtrics). These are easier to fill out, update, and make accessible.
• If your PDF is informational: Publishing the content as a web page is often better. HTML is generally more accessible, easier to maintain, and more mobile-friendly.
• Start with an accessible source document: Whether you’re working in Word, Google Docs, or InDesign, add accessibility to your source file before converting to PDF. Use heading styles, alt text, and proper table formatting so these elements carry over when you export.
• Keep accessibility settings when exporting: Always export to PDF with accessibility settings enabled. Use the “Save as PDF” or “Export as PDF” functions, not “Print to PDF,” which strips out tags and accessibility features.
• Test before sharing: Run the accessibility checks covered in this guide and, where possible, preview your PDF with a screen reader. Automated tools are helpful, but manual testing ensures your content is truly usable.

Where to start testing your PDFs

You don’t have to test every PDF you have ever published at once. Start with the documents that matter most: your highest-traffic, most-downloaded files, the forms, guides, and reports people actually open. Run each one through our free online PDF accessibility checker to see the machine-verifiable issues ranked worst-first, then work down the manual checks above and fix the source document rather than patching the exported PDF.

Accessible PDFs are easier for everyone to use, and testing them is a practical way to make a good-faith effort toward the obligations set by laws like the European Accessibility Act and to strengthen your legal position. The goal isn’t a perfect score in one sitting. It’s knowing where your documents actually stand, and fixing the worst problems first.