Understand how to create and test for an accessible PDF.
Meeting the Web Accessibility Standard
If a PDF or office document — like Microsoft Word, Excel or PowerPoint — is published on a publicly facing website, it must:
- be accompanied by an accessible HTML version that meets WCAG 2.1 at Level AA and presents the same content with the same structure
- meet the requirements in EN 301 549 Section 10 Non-web documents.
If a PDF or office document is published on an internally facing website, no HTML version is required, but the document must meet the requirements in EN 301 549 Section 10 Non-web documents.
For more information on EN 301 549 Section 10 Non-web documents, see Applying WCAG to non-web documents — Publishing PDF and office documents.
On this page
- What is PDF?
- Accessibility issues with PDFs
- Create a PDF
- Make a PDF accessible
- PDF/Universal Accessibility (UA)
- Testing PDFs
What is PDF?
PDF is a file format developed by Adobe that allows text, images, rich media, links, forms and more to be shared in a document whose layout and presentation will be the same regardless of device and operating system.
PDF documents have a .pdf file extension.
Accessibility issues with PDFs
PDFs:
- are not accessibility supported for a general public audience given their lack of reflow when viewed in a web browser on small screens, and limitations with screen readers on macOS, iOS and Android — for more on accessibility support, see the Knowledge Area: Accessibility supported technologies
- can be difficult to read, navigate and interact with using assistive technologies (AT)
- can be difficult to read on small screens.
If the PDF contains scanned images of text, these will be inaccessible to screen reader users.
PDFs can make it difficult or impossible for users to customise the presentation of content so that it’s easier to read by:
- changing font and text styles
- adjusting text height, spacing, and line length
- increasing the text size (users can try magnifying the content, but the font might pixelate and the words might not wrap.)
PDFs can also be very difficult to make accessible, depending on how complex the content’s structure is.
For more information about PDF inaccessibility, see Why GOV.UK content should be published in HTML and not PDF — GOV.UK.
Create a PDF
PDFs can be created from:
- office applications like Microsoft Word, Excel and PowerPoint
- desktop publishing and layout software like Adobe InDesign
- HTML, using the print function in common web browsers, or conversion tools in software like Adobe Acrobat.
Common software for editing accessible PDFs includes:
For free online and offline tools to manipulate PDFs, see PDF24.
Convert a document to PDF
A PDF made from another document will only be as accessible as that source document. And even then, careful, knowledgeable human inspection and remediation of the PDF itself is usually required to ensure it is as accessible as it can be. Regardless, it’s far more efficient to do as much accessibility work as you can in the source document before converting it to PDF.
See Converting documents to PDFs — PDF Accessibility — WebAIM.
To learn how to create accessible Microsoft 365 Office documents, see:
For guidance on making InDesign documents and converting to accessible PDF, see these resources from Adobe:
Make a PDF accessible
It’s currently impossible to make a PDF fully accessible to all users in a general public audience. To help ensure that a PDF is as accessible as possible and meets EN 301 549 Section 10 Non-web documents, follow the guidance below.
For more on EN 301 549, see Applying WCAG to non-web documents — Publishing PDF and office documents.
For an overall introduction to making PDFs accessible, see Creating accessible PDFs — Adobe.
For a list of handy applications to help make a PDF accessible, see PDF Accessibility Tools & Resources Roundup — DigitalA11y.
Tags and reading order
In a PDF, accessibility information is added through ‘tags’ in a separate layer from the content.
Much like HTML markup, PDF tags identify what each type of content is — for example, a heading, paragraph, list, table or image — and organises it into a hierarchical and logical ‘tag tree’.
The tag tree describes the content without impacting any of the content’s visual appearance.
The tag tree also sets the document’s reading order, the sequence that AT follow when presenting the content to users. The tag tree’s structure needs to establish a logical reading order for the content to make sense when read out by a screen reader.
For more, see About tags, accessibility, reading order, and reflow — Accessibility features in PDFs — Adobe.
Apply known accessibility techniques
The W3C’s PDF Techniques for WCAG 2 help ensure that:
- headings are created using built-in heading structures and follow a logical order
- the text is in plain language and searchable
- any foreign languages are specified
- where possible, the content can reflow to fit different screen sizes without forcing horizontal scrolling
- users can change the text colour
- the content’s semantic structure is available to assistive technology users
- meaningful images have alternative text
- tables are tagged correctly
- the reading order is logical
- colour combinations meet contrast requirements
- colour is not used as the only means to convey information
- the page title is available to assistive technology users
- the language is set so that screen readers pronounce the words correctly
See also Creating accessible PDFs — Adobe.
Scanned text
Text that is presented as an image is another common issue in PDFs. Scanned text is inaccessible to screen reader users.
If you cannot select and copy text in a PDF, the text is an image.
To address this, see PDF7: Performing OCR on a scanned PDF document to provide actual text — W3C.
Forms
Most authoring applications do not retain their fillable form fields when you convert the files to PDF. So use the forms tools in Acrobat Pro to add fillable form fields.
For more information, see:
- Work with form fields — Acrobat tutorials — Adobe
- Accessible Forms in Acrobat — PDF Accessibility — WebAIM.
See also the following PDF Techniques for WCAG 2 from the W3C:
- PDF23: Providing interactive form controls in PDF documents
- PDF10: Providing labels for interactive form controls in PDF documents
- PDF12: Providing name, role, value information for form fields in PDF documents
- PDF5: Indicating required form controls in PDF forms
- PDF22: Indicating when user input falls outside the required format or values in PDF forms
- PDF15: Providing submit buttons with the submit-form action in PDF forms.
PDF/Universal Accessibility (UA)
PDF/UA, or PDF/Universal Accessibility, is an International Organization for Standardization (ISO) standard. It primarily defines requirements for accessible PDF editing and viewing software. But it also identifies what’s needed for a PDF document to be accessible when it's used with PDF/UA conformant software.
To purchase a copy of the PDF/UA standard from the ISO, see ISO 14289-1:2014 Document management applications — Electronic document file format enhancement for accessibility — Part 1: Use of ISO 32000-1 (PDF/UA-1).
There are numerous requirements for a PDF document to be PDF/UA conformant. Two critical requirements are that:
- all meaningful content is correctly tagged
- the structure set by the tags’ order must reflect the document’s logical reading order.
The requirements in PDF/UA align with the requirements in WCAG 2.1 or EN 301 549 Section 10 Non-web documents. Techniques that help a PDF document meet PDF/UA will help it meet EN 301 549.
For more on PDF/UA, see the following from the PDF Association:
Testing PDFs
Use Acrobat Pro’s Full Check / Accessibility Check to verify that:
- the PDF has been tagged correctly and that the reading order is correct — see also the Reading Order tool for PDFs — Adobe
- the PDF has bookmarks that work as expected
- links have appropriate link text
- images have appropriate alt text
- any tables are correctly tagged
- colour contrast ratios meet requirements, and that colour alone is not used to convey meaning
- the document properties have been added, including the language of the document and the page title, and that this is set to display in the title bar of the user agent.
Other tools for testing a PDF’s accessibility, including its conformance to the PDF/UA standard, include:
See also: