PDF accessibility checker

Many organizations know the legal, business, and ethical reasons to make their websites inclusive for all visitors. Yet one type of content is regularly overlooked when it comes to creating accessible content: PDF files.

Check the accessibility of your PDF and receive immediate feedback and recommendations with 15 common accessibility issues checked. 

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Why do PDFs need to be accessible?

PDF files are one of the most popular file formats in use today. Their ability to present information in a reliable, device-independent way means many businesses include PDFs on their websites. But PDFs aren’t automatically accessible – turning a PDF into an accessible PDF requires a little extra work. The key difference between a regular PDF and an accessible PDF is that an accessible PDF can be read by people with disabilities; especially those who use assistive technologies to consume digital information.    

And with the Centers for Disease Control and Prevention (CDC) reporting that 12 million Americans have a visual disability, if your PDFs aren’t accessible, you’ll be underserving – and potentially missing out on the business of – a sizeable audience. Not only will your content be unavailable to the widest possible audience; you could also fall foul of US anti-discrimination legislation, like Section 508 of the Rehabilitation Act and the Americans with Disabilities Act. Creating accessible PDFs is therefore a key part of ensuring your website content is accessible to all visitors.  

These two laws – and other accessibility laws – refer to the foremost web accessibility guidelines: the Web Content Accessibility Guidelines (WCAG). If your PDF file meets WCAG standards it can be considered accessible.  

Best practices to make a PDF accessible

While PDFs in themselves aren’t inherently accessible, the good news is that the PDF specification does provide support for accessibility – and so all PDFs can be made accessible.  

The first thing you need to know is that an accessible PDF is a ‘tagged’ PDF. When used correctly, tags enable disabled people to navigate and read PDFs in the correct way. They do this by presenting screen readers with an alternative view; a hidden, structured outline of the PDF’s contents. Tags will not change the appearance of the PDF to other viewers. Accessible PDFs require tagging, but on its own, tagging a PDF doesn’t guarantee that it will be fully accessible.  

It’s best practice to always consider accessibility before you convert a document into a PDF. Here are some common accessibility guidelines to follow:    

  • Use tags to clearly define headings, paragraph texts, lists, tables, and alternative text for images within your PDF. Remember, automated tagging by Adobe Acrobat may be inaccurate and needs to be double-checked 
  • Ensure that the document has a logical, structured reading order. 
  • Define the language the document is published in. 
  • Links should use descriptive anchor text.  
  • Use a descriptive title for the document. 
  • Implement bookmarks so all readers can access the document’s index and overview. 
  • Use ‘Save as’ or ‘Export to PDF’ in a way that keeps tags in the document. 
  • Check that the security settings of the document enable assistive technologies to extract text. 
  • Confirm that the document opens in the correct place in the right way – so the first page in the desired size. 
  • Compress the PDF to reduce its size 
  • The PDF’s background and text should have a sufficient color contrast ratio to allow the document to be read clearly. 
  • Avoid references to content and information based on its location on the page alone. Instances of this may be meaningless to screen reader users.  
  • Don’t using text within images as it can’t be interpreted by all assistive technologies. 
  • Ensure that documents can be zoomed to enlarge text without the text becoming distorted.  

Finally, it’s a good idea to habitually use a PDF accessibility checker when uploading it to your website – or to evaluate the accessibility of your existing PDF assetsWhile it’s possible to do this manually, you can opt to automate this step by using an accessibility checker with a PDF auditing capability, like Siteimprove Accessibility.  

WCAG illustration

Advantages of using an automated accessibility tool for PDFs

PDFs are used by both the public sector and businesses to communicate everything from terms and conditions, to user guides, to reports, to fee structuresand much more besides. However, the popularity of – and the ease – of uploading PDFs means that it’s easy to lose sight of exactly how many PDFs are on a website, or even where they’re located. In some caseswebsite contributors might upload new documents, rather than systematically replacing older versions. In addition to containing obsolete information that can provide a poor user experience, the presence of multiple PDFs on a website makes it challenging and time-consuming to check that each of them adheres to the WCAG guidelines 

So, what’s the best way of checking your PDF's accessibility? Using an automated accessibility tool that lists all PDFs on your website, detects accessibility issues within them, and provides detailed guidance on remediation.   

Tools like the Siteimprove PDF accessibility checker are an easy, efficient way of ensuring that your PDFs are fully compliant with accessibility legislation and UX best practice. They also eliminate the possibility of human error when it comes to validating long, complex PDFs. Incorporating an accessibility checker into your content workflow is a good way to ensure your website visitors don’t know about inaccessible PDFs before you do.  

For those completing a content audit, a website redesign, or an accessibility project, an automated accessibility tool is also invaluable for working through this process efficiently, accurately, and at scale.  

What does Siteimprove check for in PDFs? 

Siteimprove runs the following automated checks for common web accessibility issues in your PDF files:  

  • The document is not machine-readable 
  • The document is not tagged 
  • The document is missing a language definition 
  • The document has no title 
  • The document contains no headings 
  • The document has no bookmarks 
  • Document cannot be accessed by user agents 
  • The document contains untagged content 
  • The first heading is not a Heading 1 
  • The heading structure is incorrect 
  • The image has no alternative presentation 
  • The table has no table headings 
  • The form element does not have a label explicitly connected 

These issues are explained in detail within the tool, with actionable explanations for how to fix each PDF accessibility error. It’s a good idea to combine accessibility checks with Siteimprove’s Quality Assurance module, which flags broader user experience issues, like broken links, in your PDFs.