ShadowToolkit

Contrast Checker

Contrast Checker running client-side on your device.

100% In-Browser
100% In-Browser PrivacyLocal

Your files and data are processed locally and never leave your device.

WCAG 2.1 Color Contrast Checker

Evaluate accessibility contrast compliance for normal text, large text, and UI elements.

WCAG Contrast Ratio
13.98:1
AAA Enhanced Level
Normal Text (<18pt)
AA (4.5:1) Pass
AAA (7.0:1) Pass
Large Text (≥18pt or Bold)
AA (3.0:1) Pass
AAA (4.5:1) Pass
UI Components & Icons
WCAG 2.1 (3.0:1) Pass

Accessible Headline Text Example

Good design is accessible to everyone. Contrast ratios measure the difference in perceived luminance between text and background colors under WCAG guidelines.

Interactive UI Button

What is Contrast Checker?

Color Contrast Checker evaluates visual accessibility between text and background colors according to World Wide Web Consortium (W3C) WCAG 2.1 standards. It calculates precise relative luminance ratios, providing instant Pass/Fail ratings for Normal Text, Large Text, and UI Components.

Zero-Server Client-Side Guarantee

Unlike legacy online utilities that upload sensitive media and documents to remote cloud storage, Shadow Toolkit executes this entire operation directly within your browser's local runtime. Your raw data never crosses the network.

Key Capabilities

  • Calculates exact contrast ratio (e.g. 4.5:1, 7.1:1, 14.2:1) based on WCAG 2.1 algorithms
  • Pass/Fail badges for WCAG Level AA and Level AAA (Normal Text, Large Text, UI Components)
  • Live interactive preview simulating simulated color vision deficiencies (Protanopia, Deuteranopia, Tritanopia)
  • Smart 'Auto-Adjust Color' suggestion to fix failing ratios by nudging lightness
  • 100% private client-side accessibility testing

Common Use Cases

1Auditing website button, text, and form field color pairings for ADA and WCAG compliance
2Testing mobile application color schemes for readable daylight outdoor usage
3Ensuring design system color tokens meet legal accessibility requirements
4Creating consistent, accessible UI components and modern aesthetic design tokens for digital products

How to use Contrast Checker

01

Set Foreground Color

Enter the text or icon color (HEX/RGB).

02

Set Background Color

Enter the container or page background color.

03

Check WCAG Compliance

Review the contrast ratio and Level AA / AAA compliance badges.

04

Copy CSS or Export Assets

Copy the generated production-ready CSS snippet, Tailwind classes, or SVG assets directly into your design system.

Frequently Asked Questions

WCAG Level AA requires a minimum contrast ratio of 4.5:1 for normal text (under 18pt/24px) and 3:1 for large text (18pt+ or 14pt bold).

Related Tools

Local

Color Picker & Converter

Pick colors, convert HEX/RGB/HSL, and test WCAG accessibility contrast.

Use Tool
Local

Palette Generator

Palette Generator running client-side on your device.

Use Tool
Local

Random Color Generator

Random Color Generator running client-side on your device.

Use Tool
Local

CSS Box Shadow Generator

Generate custom CSS box shadows visually.

Use Tool