FileopiaColor Contrast Checker (Free Online)
Color Contrast Checker (Free Online) Fast, secure, browser-local processing with zero file limits.
- Upload
- Options
- Download
- ✓ 100% free
- ✓ No sign-up
- 🔒 Files never leave your device
How to: Color Contrast Checker (Free Online)
- Choose text color and background color.
- View the calculated contrast ratio (e.g. 4.5:1).
- Verify WCAG AA and AAA pass/fail badges.
Why use Fileopia for Color Contrast Checker (Free Online)?
| Fileopia | Typical upload-based sites | |
|---|---|---|
| What you type is sent to a server | No – stays in your browser | Often |
| Sign-up required | Never | Often for bigger jobs |
| Hourly / daily task limits | None | Common on free plans |
| Works offline after loading | Yes, for most tools | No |
Private by design
Everything you type is calculated by JavaScript in this tab. Nothing is sent to Fileopia or anyone else, and there are no accounts or tracking cookies tied to what you enter.
- Test it yourself: once this page has loaded, switch off Wi‑Fi or mobile data and run the tool – it keeps working.
- Check the network: open your browser’s developer tools (F12 → Network) while processing; you will see no file upload requests.
- Nothing to delete: close the tab and the data is gone – there is no server copy, no retention period and no account.
File tools designed for local processing work in your browser. Practical file-size and performance limits depend on the selected tool, browser and device. Some features need an internet connection to load code or data.
Frequently asked questions
What is the minimum WCAG AA contrast ratio?
Normal text requires at least 4.5:1, and large text (18pt+) requires 3:1.
Is Color Contrast Checker (Free Online) really free?
Yes. Every tool on Fileopia is free to use with no account required and no watermarks; practical file limits vary by tool and device. The site is supported by unobtrusive ads.
Are my files uploaded to a server?
No. Fileopia processes your files directly in your browser using JavaScript. Your documents never leave your device, so they stay completely private.
Does it work on mobile?
Yes. Fileopia works in any modern browser on Android, iPhone, iPad, Windows, Mac and Linux.