Now in Alpha

Convert PDFs toAccessible HTML

Convert PDFs into WCAG-ready HTML with semantic structure, MathML equations, and AI-generated image descriptions.

Start FreeSee How It Works

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Per page processing

WCAG 2.1 AA

Validated with every file

10 pages

Free trial, no card required

Built for Complex Documents

Textbooks, lecture notes, research papers, exam materials — we handle the content types that trip up other converters.

Smart AI Processing

Intelligent routing sends each page to the optimal conversion method — fast processing for simple content, advanced analysis for complex layouts.

Equation Recognition

Printed and handwritten equations are converted to native MathML that screen readers can speak aloud.

Intelligent Alt Text

AI analyzes images and generates descriptive, contextual alt text. Diagrams, charts, and photos — all described accurately.

Table Structure

Complex tables with merged cells and headers are converted to properly structured HTML with accessibility attributes.

WCAG Validation

Every output is validated against WCAG 2.1 AA. Common issues are auto-fixed, and you get a downloadable compliance report.

Hosted Shareable URLs

Get a permanent link for every converted document. Share with colleagues, embed in your LMS, or replace your PDF links — we host it for free.

Why Convert to HTML?

PDF was designed for print. HTML was designed for people. Here's how they compare for accessibility.

Screen Reader Support

PDF

Requires manual tag tree; often missing or broken

HTML

Native semantic elements understood by all screen readers

Reflowable Content

PDF

Fixed layout — requires horizontal scrolling on small screens

HTML

Adapts to any screen size, zoom level, or user preference

Math Equations

PDF

Flattened images or drawn glyphs — no semantics

HTML

Native MathML that screen readers can speak aloud

Table Accessibility

PDF

Tagged table structures are brittle and often wrong

HTML

<th>, scope, and headers attributes are well-understood

User Customization

PDF

Fixed colors, fonts, and spacing

HTML

Users can override contrast, fonts, spacing, and dark mode

AI & LLM Processing

PDF

Lossy text extraction; structure and reading order are guessed

HTML

Semantic markup preserves structure — ideal for AI workflows

Validation Tooling

PDF

Few tools (PAC, Adobe Preflight)

HTML

Hundreds of tools (axe, Lighthouse, WAVE, pa11y, and more)

Print Fidelity

PDF

Pixel-perfect rendering guaranteed

HTML

Depends on CSS print styles — good but not identical

PDF excels at print fidelity and legal archival. For everything else — accessibility, screen readers, AI processing, mobile devices — HTML is the better format. That's why we convert your PDFs to semantic, accessible HTML.

Two Steps to Accessibility

1

Drag & Drop Your PDF

Drop your file or select it from your computer. PDFs up to 50 MB with any number of pages.

2

Share or Download

Get a hosted shareable URL for your accessible HTML — or download it. Preview for free, then purchase credits to unlock the final version.

What We Test

Every converted document is validated against WCAG 2.1 Level AA using 45+ custom rules, axe-core browser auditing, and specialized accessibility checks. Issues we can fix are fixed automatically.

Document Structure

  • Title, language declaration, viewport meta
  • Valid lang attribute value (ISO language code)
  • Language of parts (lang on foreign-language passages)
  • Sequential heading hierarchy (h1 → h2 → h3)
  • Empty headings detected and flagged
  • Landmark regions (main, nav, header, footer)
  • Skip navigation link
  • Unique element IDs

Images & Alt Text

  • AI-generated descriptive alt text for every image
  • Alt text quality — no generic placeholders
  • Decorative images marked as presentational
  • SVG and role="img" elements labeled
  • Images of text detected (SC 1.4.5)

Tables & Lists

  • Header cells with scope attributes
  • Empty table headers detected
  • Proper list structure (ul/ol with li only)
  • Definition list structure (dl/dt/dd)
  • Layout tables marked role="presentation"

Color & Visual

  • Color contrast — 4.5:1 normal, 3:1 large (AA)
  • Content readable at 200% zoom (browser test)
  • WCAG 1.4.12 text spacing overrides (browser test)

Keyboard & Navigation

  • Focus order matches visual reading order
  • No positive tabindex disrupting flow
  • Interactive elements not removed from tab order
  • Links and buttons have discernible text

Math & Equations

  • Equations converted to native MathML
  • Math elements have alt text / aria-labels
  • Equations use screen-reader-compatible markup

ARIA & Semantics

  • Valid WAI-ARIA roles
  • ARIA attributes match element roles
  • Invalid HTML nesting detected (block inside inline)

Auto-Remediation

When axe-core finds violations, our fix loop automatically repairs 20+ common issue types — missing landmarks, heading order, contrast, ARIA attributes, and more. The document is re-audited after each fix to confirm no regressions. Up to 3 iterations run before finalizing.

Limitations of Automated Testing

Color as sole information carrier

Detecting whether color is the only means of conveying information (e.g. in charts or status indicators) requires semantic analysis beyond current automated capabilities. Contrast ratios are verified mathematically.

Screen reader pronunciation

Automated tools verify structure, but cannot hear what a screen reader actually speaks. We ensure correct semantic markup so screen readers have the right information.

Subjective reading order

We verify focus order and heading hierarchy programmatically. Complex multi-column layouts may need human judgment for optimal reading flow.

Cognitive accessibility

Language complexity, reading level, and cognitive load are not measured. Our output preserves the source document's language.

Complex interaction patterns

We test keyboard tab order and focus management. Multi-key shortcuts or custom widget interactions in source content are beyond automated testing.

Color blindness simulations

We enforce contrast ratios mathematically. Simulating deuteranopia, protanopia, or other conditions requires specialized tools.

View a Sample Audit Report

Frequently Asked Questions

We automatically do an AI-driven visual comparison of the rendered HTML output and the PDF input. If the result does not meet our standards for accuracy, we attempt to fix it. If the output cannot be fixed, we will abort the conversion and notify the user. It is possible to provide PDF input that cannot be reliably processed, but it is rare. Every conversion has an unconditional 30 day money-back guarantee. Click the feedback button at the bottom of any page and just tell us what happened.
We list on the website and on every conversion exactly which WCAG requirements we test against. Every document has a 30 day no questions asked money back guarantee.
We detect complex layouts visually and compare the output with the input - but our goal is accessibility. We have to sacrifice layout complexity for accessibility, we will.
Scanned PDF are a special case. We detect a PDF that was created on a scanner and only contains pictures of documents rather than document content and processes that PDF in a completely different workflow. Any text on each page is extracted and any images are analyzed and an appropriate alt-text tag is created. Then the images are recreated in the HTML with the alt tag and any recognized text.
Yes. Extracting and formatting equations from PDFs is a challenge. We automatically detect equations in the source PDF and use best-of-breed equation recognition solutions to extract the equation, format it properly and insert it into the HTML.
Every document is validated against WCAG 2.1 AA standards. We auto-fix common issues and flag anything requiring manual review. You can download a compliance report for each conversion.
The Enterprise plan includes API access and webhooks.
We produce WCAG-compliant HTML. Every conversion includes an analysis of what the document was tested against and any warnings or failures.
We use a combination of cloud-based and on-site servers with automatic failover to multiple providers. We distribute AI calls to at least three different providers to process tasks in parallel and isolate the system from failures in any one provider. It is very reliable.
The generated HTML can automatically be stored on any S3-compatible storage system. Self-hosted storage is available on Department and Enterprise plans only.
View all 25 frequently asked questions

Start Making PDFs Accessible

Preview your accessible HTML for free — no credit card required. Purchase credits to unlock the final hosted URL, starting at $0.20 per page.

Try Free — 10 Pages