What is the best free tool to make a PDF accessible?

It depends on your document. For checking: PAC 2024 (Windows, free) is the industry standard. For fixing simple documents where you have the source: Microsoft Word or LibreOffice, with export to tagged PDF. For WCAG 1.4.10 Reflow (the requirement no PDF tool can fix): toolkit.bot converts PDFs to EPUB3 for free — EPUB3 is reflowable by design and satisfies Reflow structurally.

Can I make a PDF WCAG 2.1 AA compliant for free?

For most WCAG 2.1 AA criteria (tagging, alt text, contrast, reading order), yes — using PAC 2024 to check and Word/LibreOffice to fix. The exception is WCAG 1.4.10 Reflow: no free tool can make a complex PDF satisfy this requirement while keeping it as a PDF. The free solution is conversion to EPUB3 using toolkit.bot — EPUB3 satisfies Reflow by design.

Does WCAG 1.4.10 Reflow apply to PDFs?

Yes. WCAG 1.4.10 Reflow is a Level AA requirement, meaning it is mandatory for EAA 2026 and ADA Title II compliance. It requires content to be readable at 320px equivalent viewport width without horizontal scrolling. PDF is a fixed-layout format and cannot reflow — this is a format limitation, not a tagging problem. The only fix is to use a reflowable format like EPUB3 or HTML.

How to Make a PDF Accessible for Free (2026 Guide)

Accessibility checkers flagged your PDF. Now what?

This guide covers every free tool available for making PDFs accessible in 2026, what each one can and cannot do, and the fastest path to WCAG 2.1 AA compliance without paying for Adobe Acrobat Pro.

What “accessible PDF” actually means

An accessible PDF must meet WCAG 2.1 Level AA. The key requirements:

Tagged structure: headings, lists, tables, and reading order defined in PDF tags
Alt text: images have text descriptions
Color contrast: body text at ≥4.5:1 ratio; large text at ≥3:1
No color-only information: charts, warnings, status indicators use text or shape, not only color
WCAG 1.4.10 Reflow: content readable at 320px viewport width without horizontal scrolling

The last requirement is the one no free tool can fix while keeping the file as a PDF.

Free tools for PDF accessibility

PAC 2024 (free — Windows)

The industry-standard checker for PDF/UA compliance. Free, maintained by the PDF Association.

Does: Checks existing PDFs against PDF/UA-1 and WCAG. Reports failures with criterion references.

Does not: Fix anything. PAC 2024 is a checker, not an editor.

Best for: Auditing your current PDFs.

Microsoft Word (free with Microsoft 365)

If you have the original Word source, fixing it in Word is the best free path.

Does: Built-in Accessibility Checker finds alt text, heading structure, and table header issues. Export to tagged PDF via File > Save As > PDF with accessibility tags enabled.

Does not: Fix WCAG 1.4.10 Reflow for complex layouts.

Best for: Simple single-column documents where you have the source file.

LibreOffice Writer (free, all platforms)

Free open-source alternative to Microsoft Office. Can export accessible tagged PDFs.

Does: Exports tagged PDFs with heading structure and alt text when using correct export settings.

Does not: Remediate complex existing PDFs not created in LibreOffice.

Best for: Creating new accessible documents from scratch.

ACE by DAISY (free — all platforms)

The standard EPUB3 accessibility checker. After converting your PDF to EPUB3 (see below), ACE validates WCAG 2.2 AA compliance.

Does: Validates EPUB3 against WCAG 2.2 AA and EPUB Accessibility 1.1. Generates HTML compliance reports.

Install: npm install -g @daisy/ace

toolkit.bot (free tier — all platforms)

toolkit.bot converts PDFs to EPUB3 with EPUB Accessibility 1.1 structure. The only automated free tool that produces output satisfying WCAG 1.4.10 Reflow.

Does: Converts PDF to reflowable EPUB3, applies accessibility tags, verifies output. Free tier: 5 conversions/month, no account required.

Unique capability: EPUB3 is HTML5-based and adapts to any screen width — satisfying WCAG 1.4.10 by design.

The WCAG 1.4.10 Reflow problem

WCAG 1.4.10 (Level AA) requires content to be readable at 320px viewport width without horizontal scrolling. PDF is a fixed-layout format — page dimensions are baked in. A two-column document designed for A4 cannot reflow to a mobile viewport.

No amount of tagging fixes this. It is a format problem, not a tag problem.

The only free solution: Convert the PDF to EPUB3. EPUB3 is reflowable by design. toolkit.bot does this free.

Step-by-step: make a PDF accessible for free

Simple documents (single-column, you have the source):

Run PAC 2024 to identify failures
Fix in Word or LibreOffice source, re-export to tagged PDF
Re-run PAC 2024 to confirm

Complex documents or WCAG 1.4.10 required:

Go to toolkit.bot/pdf2epub
Upload your PDF
Download the EPUB3 output
Run ACE by DAISY: ace your-file.epub -o ace-report
Review the ACE report for WCAG 2.2 AA pass/fail
Distribute EPUB3 as your accessible format

Tool comparison

Tool	Cost	Checks	Fixes	Fixes Reflow
PAC 2024	Free	✓	✗	✗
Microsoft Word	Free*	✓	✓ (source)	Partial
LibreOffice	Free	✓	✓ (source)	Partial
Acrobat Reader	Free	Basic	✗	✗
Acrobat Pro	$239/yr	✓	✓	✗
ACE by DAISY	Free	✓ (EPUB)	✗	n/a
toolkit.bot free	Free	✓	✓ (converts)	✓

*Requires Microsoft 365 or one-time purchase

Convert any PDF to accessible EPUB3 — the only free solution that satisfies WCAG 1.4.10 Reflow. No account required.

Try free → See all plans