Color Contrast Ratio Calculator (WCAG)

Calculate exact luminance contrast ratio (1:1 to 21:1) between foreground and background colors.

How It Works & Processing Standards

Calculate exact luminance contrast ratio (1:1 to 21:1) between foreground and background colors.

Your input data is never sent to any server and is securely processed on your device.

Current Limits

  • Maximum input length: 100,000 characters

Color Contrast Ratio Calculator (WCAG) is a 100% free, browser-based online utility. All calculations and file conversions run locally inside your browser (Local-First) without sending data to remote servers, keeping your documents and inputs strictly private.

How to Use Color Contrast Ratio Calculator (WCAG)

  1. 1
    Select ColorsEnter foreground text color and background color.
  2. 2
    Inspect RatioReview calculated contrast ratio (e.g. 7.42:1) and relative luminances.

Common Use Cases

  • Verifying design system color accessibility and preparing compliance audits
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