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flowtools/Contrast Checker

Contrast Checker

Check WCAG color contrast ratios for accessible designs.

Sample Text Preview

This is how body text looks against this background.

Results

15.52:1

AAA (Enhanced)7:1
AA (Minimum)4.5:1
AA Large Text3:1

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How it works

  1. 1

    Pick or type a foreground color and a background color.

  2. 2

    See the contrast ratio and WCAG compliance level instantly.

  3. 3

    Preview the text rendering live on your chosen background.

Why choose FlowTools

  • Test AA, AA Large Text, and AAA compliance levels simultaneously.
  • Live color picker and hex input — no page reloads needed.
  • Sample text preview shows exactly how your colors render together.
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Frequently Asked Questions

AA (minimum) requires 4.5:1 for normal text and 3:1 for large text. AAA (enhanced) requires 7:1 and 4.5:1 respectively.
Using the WCAG 2.1 relative luminance formula, which weights RGB channels according to human perception.
Currently supports hex colors (#ffffff). RGB and HSL support coming soon.