Why limit to 20 pages?

Rasterising every page is slow. For longer documents, run the tool on excerpts or rely on a desktop tool like Adobe Acrobat's Accessibility Checker for full coverage.

What is WCAG-AA 4.5:1?

The Web Content Accessibility Guidelines AA-level threshold for normal text. Large text (18pt+ or 14pt+ bold) has a relaxed 3:1 threshold.

Are the files uploaded?

No — rasterisation and sampling all happen in your browser.

Color Contrast Checker

Sample text-run and background colors across a PDF and flag pairs that fall below WCAG-AA contrast ratios.

Your files never leave your browser. All processing happens on your device — nothing is uploaded.

1. Upload your file

How does the Color Contrast Checker work?

Audit a PDF for low-contrast text. The tool rasterises up to 20 pages, samples a few text-bearing pixels per page, and computes the WCAG contrast ratio between the apparent foreground and background colours. Pairs below WCAG-AA (4.5:1 for normal text) are flagged with their hex colours and the actual ratio. This is a heuristic — it cannot perfectly identify which pixel is text versus background, and it samples only a few items per page — so confirm flagged pairs visually before fixing them in the source document.

🔒 Security & Privacy

All processing happens on your device. Your files never leave your browser, never touch our servers, and are not stored anywhere. Close the tab and the file is gone.

📱 Use it on any device

Works in any modern browser — Mac, Windows, Linux, iPhone, Android, and tablets. No installation, no app to download. Just open the page and start.

⚡ Quick & easy

Drag, drop, click. Most files process in seconds, not minutes. No watermarks added to your output, no per-day limits, and the tool always shows the result before asking you to download.

🎁 Always free, no signup

Free to use, every time. No account creation, no email required, no “trial” that converts to a paid plan. We make money from ads so you don’t have to pay.

Frequently asked

No — it's a heuristic. The tool rasterises pages and samples around text-item origins, picking the darkest and lightest pixels in a 5×5 neighbourhood. Real contrast checking requires per-character rendering instrumentation that is out of scope.