What Is an Accessible PDF?
An accessible PDF is a document with real text and a logical, machine-readable structure, so people can understand and navigate it with a screen reader, magnifier, keyboard, or other assistive technology.
The visible page may look exactly like a regular PDF. The difference is underneath: an accessible file identifies headings, paragraphs, lists, figures, tables, links, language, and reading order. WCAG 2.1 AA describes accessibility outcomes for web content, while PDF/UA (ISO 14289) defines requirements for accessible PDF technology.
The six requirements of an accessible PDF
Structural tags
Tags identify the document, headings, paragraphs, lists, tables, figures, formulas, and other elements. They let screen reader users move by heading instead of listening from page one.
Correct reading order
The tag order must follow the intended meaning. Multi-column pages, sidebars, footnotes, and captions often need manual repair after automatic tagging.
Useful text alternatives
Meaningful figures need alt text that communicates their purpose. Decorative images should be marked as artifacts so they are skipped.
Table headers and associations
Header cells must be marked as TH rather than TD and associated with the data cells they describe. Complex tables may need row or column scope set manually.
A declared document language
The default language controls screen-reader pronunciation. A file can also mark passages that switch to another language.
Real, selectable text
Text cannot exist only as pixels. Scans need OCR, and scientific notation needs semantic reconstruction rather than a rough line of recognized characters.
See a direct PDF versus accessible PDF comparison or go deeper on tagged PDF structure.
How to check if your PDF is accessible
Start with an automated check, then verify the result by hand. Adobe Acrobat Pro's accessibility check can find missing tags, title, language, and common structural errors. PAC, maintained by the PDF/UA community, tests PDF/UA and WCAG-related criteria. Underleaf's free PDF accessibility checker provides a private first pass in your browser.
- Inspect the tag tree and reading order, not only the pass count.
- Read representative pages with NVDA, JAWS, or VoiceOver.
- Navigate every link and form field with a keyboard.
- Check whether figure descriptions and math make sense when heard.
How to create an accessible PDF
Build accessibility into the source whenever you can. In Word, use heading styles, real lists, simple tables with header rows, alt text, and the tagged-PDF export option. In Google Docs, use the heading menu, alt text, descriptive links, and simple tables, then inspect the exported PDF because tag quality can vary. In LaTeX, use the current tagging workflow beginning with \DocumentMetadata and test the generated structure.
Existing PDFs need remediation: establish a text layer, build or repair tags, set reading order, add alt text, repair tables, and verify the result. The full process is in How to Make a PDF Accessible.
Why math is the hardest part
A Formula tag only identifies an object as math; it does not encode how the expression should be spoken. Accessible math needs a meaningful alternative such as MathML. A photograph of an equation and ordinary OCR output do not supply that semantics. Underleaf can send sample STEM pages below into accessible formats.
Who is required to provide accessible PDFs?
Requirements depend on the organization and how the document is used. The U.S. Department of Justice's Title II web rule applies WCAG 2.1 AA to web content, including many posted documents, provided by state and local governments. An April 2026 interim rule moved the compliance dates to April 26, 2027 for entities serving 50,000 or more people and April 26, 2028 for smaller entities and special district governments.
Section 504, Section 508, state rules such as Texas 1 TAC 213, and institutional policies may create additional duties. Course materials, forms, reports, agendas, and library documents can all be in scope depending on the facts. For the current Title II rule, see the official DOJ fact sheet.
This guide explains document practice, not legal advice. Confirm the rules that apply to your institution and material.
For institutional services, see Underleaf accessibility solutions and PDF remediation for STEM content.
Have handwritten or scanned STEM content?
Underleaf converts handwritten notes, scanned PDFs, and equations into accessible MathML, tagged PDF/UA, HTML, and clean LaTeX. Send us two or three pages for a free sample. There is no charge and no commitment.