Is Contrast Checker really free?

Yes, Contrast Checker is completely free to use with no signup, no credit card, and no hidden fees. The free tier supports files up to 10 MB and processes them entirely in your browser. Pro and Business subscriptions unlock larger files and faster batch operations, but the core tool stays free forever.

How secure is Contrast Checker?

Contrast Checker processes your files entirely inside your browser using WebAssembly, which means they never reach our servers and we have zero access to your file contents. When a server-side step is unavoidable, the file is encrypted in transit, processed in an isolated worker, and auto-deleted within 30 minutes.

What file size does Contrast Checker support?

Free users can process files up to 10 MB per upload, which covers most PDFs, photos, and documents. Pro subscribers can work with files up to 100 MB, and Business subscribers up to 500 MB. Browser-based tools have no hard server limit since processing happens locally on your device.

How long does Contrast Checker take?

Browser-based runs of Contrast Checker usually finish in two to five seconds on a modern laptop or phone, because the heavy work happens locally with WebAssembly. Larger files and server-side operations may take ten to thirty seconds. AI-backed tools depend on prompt length but generally respond in under five seconds.

Do I need to install software for Contrast Checker?

No installation, browser extension, or native app is needed to use Contrast Checker. The tool runs in any modern web browser on desktop, tablet, or phone. Just open the page, drop your file in the upload zone, choose the options, and process. Nothing is added to your operating system.

What browsers does Contrast Checker support?

Contrast Checker works in every modern browser, including Chrome, Edge, Firefox, Safari, Brave, and Opera, on desktop and mobile. We test against the two most recent major versions of each engine. If a feature requires a newer API the page will clearly mark it as unsupported instead of failing silently.

Can I use Contrast Checker on mobile?

Yes, Contrast Checker runs fully in the browser on iOS and Android phones and tablets with no app install required. Touch targets are sized for fingers, file pickers integrate with the OS share sheet, and the layout adapts to portrait or landscape. Performance is comparable to a low-end laptop on most tools.

What happens to my file after using Contrast Checker?

When Contrast Checker can run locally, your file never leaves the device and is discarded as soon as the result is downloaded or the tab closes. When a server step is required, the upload is encrypted in transit, processed in an isolated worker, and auto-deleted within 30 minutes via cron.

Contrast Checker — Free Online Tool

Use instantly, free, with no signup. Your files are processed locally and never uploaded.

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Sample text

The quick brown fox jumps over the lazy dog

Foreground

Background

Contrast ratio

17.40 : 1

AA Normal: Pass

AA Large: Pass

AAA Normal: Pass

AAA Large: Pass

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How To Use Contrast Checker

Select your file to process

Processing happens instantly in your browser

Download your result — no email or account needed

Key Features Contrast Checker

Files processed locally — never uploaded to any server

Lightning fast browser-based processing with WebAssembly

No account, no signup, no registration required

100% free for all standard use cases

Available in 70 languages worldwide

Works on any device: desktop, tablet, and mobile

Your Files Stay Private

All processing happens in your browser using WebAssembly. Your file is never sent to our servers. We have zero access to your files — guaranteed.

Frequently Asked Questions

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