Analyze TOOLKIT

WCAG Contrast Checker

Accessibility verification studio. Calculate exact contrast ratios, evaluate WCAG 2.1 AA/AAA compliance, and test against live buttons, cards, and headings.

Client-Side Engine

Executed locally via HTML5 Canvas & Web API. Zero server upload.

TEXT / FOREGROUND COLOR

CONTAINER / BACKGROUND

WCAG 2.1 CONTRAST RATIO

21.00:1

PASSED LEVEL AAA (MAXIMUM)

WCAG Conformance Status Matrix

Normal Text AA (4.5:1)

PASS

Body text (<18pt)

Normal Text AAA (7:1)

PASS

Enhanced body text

Large Text AA (3.0:1)

PASS

Headings (>18pt)

Large Text AAA (4.5:1)

PASS

Enhanced headings

UI Components (3.0:1)

PASS

Inputs, icons & borders

Realistic Live UI Component Previews

RENDERED USING SELECTED PAIR

The Typography & Readability Preview

Good contrast ensures effortless legibility for readers with low vision, color deficiencies, or users navigating websites in harsh outdoor sunlight. Typography must stand out with uncompromising clarity.

Form Input:name@example.com

Status Badge

Nested Component Card

Borders, icons, and interactive form fields must maintain at least a 3.0:1 contrast ratio against the adjacent canvas surface.

WORKFLOW PROTOCOL

How to Use This Tool

Set Foreground

Input the text or icon color hex code (#FFFFFF, #000000, etc.) or choose from presets.

Set Background

Input the canvas or container background hex code, or use the Swap button to invert roles.

Evaluate Compliance

Inspect calculated WCAG 2.1 contrast ratios against Level AA and Level AAA accessibility standards.

Preview & Auto-Fix

Test live UI components (buttons, cards, headings) or click Auto-Suggest to calculate the nearest compliant shade.

TECHNICAL EXPERTISE & METHODOLOGY

Frequently Asked Questions

What are the WCAG 2.1 Level AA and AAA contrast ratio thresholds?+

For Level AA compliance, standard body text requires a minimum contrast ratio of 4.5:1, while large text (18pt or 14pt bold) requires at least 3.0:1. For Level AAA (enhanced accessibility), standard text requires 7.0:1 and large text requires 4.5:1. User interface components and graphical objects require at least 3.0:1.

How is relative luminance mathematically determined in WCAG 2.1?+

Relative luminance (L) normalizes sRGB channels using gamma expansion: values <= 0.03928 are divided by 12.92, while larger values are calculated as ((C + 0.055) / 1.055)^2.4. Luminance is then computed as L = 0.2126*R + 0.7152*G + 0.0722*B. The contrast ratio is (L1 + 0.05) / (L2 + 0.05).

What does the Auto-Suggest Accessible Color button do?+

The auto-suggest algorithm calculates the background luminance and iteratively steps the foreground color’s lightness channel until the mathematical threshold (4.5:1 or 7.0:1) is achieved with minimal deviation from your original hue.

INTERCONNECTED WORKFLOW