What color formats are supported?

Our color tools support HEX, RGB, RGBA, HSL, HSLA, CMYK, and named CSS colors. You can convert between any of these formats instantly.

How do I check color contrast?

Our Contrast Checker compares two colors (foreground and background) and reports the contrast ratio along with WCAG AA and AAA compliance status for both normal and large text.

Can I generate a color palette?

Yes. Use the Color Palette Generator to create harmonious color schemes based on color theory rules including complementary, analogous, triadic, and tetradic harmonies.

What is a color blind simulator?

The color blindness simulator shows how your design appears to people with different types of color vision deficiency including protanopia, deuteranopia, and tritanopia.

Color Contrast Checker

Free online color contrast checker. Check WCAG AA/AAA compliance. Perfect for designers and developers.

Foreground

Luminance: 0.0000

Background

Luminance: 1.0000

Contrast Ratio

21.00:1

WCAG AA (Normal) (4.5:1)Pass

WCAG AA (Large) (3:1)Pass

WCAG AAA (Normal) (7:1)Pass

WCAG AAA (Large) (4.5:1)Pass

Normal Text (16px) — The quick brown fox

Large Text (24px bold) — The quick brown fox

Embed this tool

Copy and paste the code below into your website to embed this tool for free. An attribution link to The Util Box is required.

<iframe src="https://www.theutilbox.org/embed/contrast-checker" width="600" height="500" frameborder="0" style="border: none; max-width: 100%;" title="Free Color Contrast Checker tool from The Util Box"></iframe>
<!-- Free tool by The Util Box — https://www.theutilbox.org/tools/contrast-checker -->
<a href="https://www.theutilbox.org/tools/contrast-checker">Color Contrast Checker by The Util Box</a>

Frequently Asked Questions about Color Contrast Checker

What Is Color Contrast Checker?

Free online color contrast checker. Check WCAG AA/AAA compliance. Perfect for designers and developers. Whether you need a quick calculation, text transformation, or data conversion, this free online colors design tool delivers instant results entirely in your browser — no server uploads, no sign-ups, and no data leaves your device.

How to Use the Free Color Contrast Checker Online

Enter your input — type, paste, or select data in the provided field.
Adjust options — tweak any available settings or parameters to match your needs.
Get instant results — output appears immediately as you type or after clicking a button.
Copy or export — use the copy button to grab the result for use elsewhere.

All processing happens client-side using JavaScript, so your information never leaves your computer. This free online colors design tool requires no registration and works on any modern browser.

Why Choose Our Free Color Contrast Checker Tool?

100% free — no hidden premium tiers or usage limits.
Fully private — runs entirely in your browser; no data is sent to any server.
Instant & fast — results appear in milliseconds with zero load times.
Works offline — after the first load, the tool is available without an internet connection.
No sign-up — open the page and start using it immediately.

Color Contrast Checker — Quick Reference

Feature	Details
Category	colors design
Processing	100% client-side (browser)
Privacy	No data leaves your device
Cost	Free — no sign-up required
Works Offline	Yes (after first load)