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#312e81 on #ffffff contrast ratio

11.42:1

Dark blue (Tailwind indigo-900) text (#312e81) on a white background (#ffffff) meets WCAG 2.2 level AAA for normal text.

Swap: #ffffff on #312e81

Large text sample

Normal body text in #312e81 on #ffffff. The quick brown fox jumps over the lazy dog.

WCAG 2.2 results

WCAG 2.2 contrast results for #312e81 on #ffffff
Normal text — WCAG 1.4.3 AA4.5:1Pass
Large text — WCAG 1.4.3 AA3:1Pass
UI components & icons — WCAG 1.4.11 AA3:1Pass
Normal text — WCAG 1.4.6 AAA7:1Pass
Large text — WCAG 1.4.6 AAA4.5:1Pass

Nearest passing colours

This pair already meets AAA. Nothing to fix.

How it looks with colour blindness

Simulated with the Machado et al. (2009) model at full severity.

  • Aa

    Protanopia (no red cones)

    10.49:1

  • Aa

    Deuteranopia (no green cones)

    11.44:1

  • Aa

    Tritanopia (no blue cones)

    10.89:1

  • Aa

    Achromatopsia (no colour)

    11.37:1

Try a different pair

Colours

Hex, rgb() or hsl(). Alpha is composited.

Permalink

Preview

Large heading text

Normal body text at 14 px. The quick brown fox jumps over the lazy dog.

Outlined buttonA text link

Colour-blindness preview

Simulated with Machado et al. (2009), full severity.

  • AaProtanopia (no red cones)10.49:1
  • AaDeuteranopia (no green cones)11.44:1
  • AaTritanopia (no blue cones)10.89:1
  • AaAchromatopsia (no colour)11.37:1

Contrast ratio

11.42:1

WCAG 2.2 contrast verdicts
CheckCriterionNeedsResult
Normal text1.4.3 AA4.5:1Pass
Large text1.4.3 AA3:1Pass
UI components & graphics1.4.11 AA3:1Pass
Normal text1.4.6 AAA7:1Pass
Large text1.4.6 AAA4.5:1Pass

Nearest passing colours

Same hue, lightness adjusted in OKLCH.

AA — 4.5:1

Already passes.

AAA — 7:1

Already passes.

Large text means at least 24 CSS px, or 18.66 CSS px bold. Ratios are truncated, never rounded, so 4.49:1 is shown as failing 4.5:1.

Questions about this pair

Is #312e81 on #ffffff accessible?
Yes for WCAG 2.2 level AA: the contrast ratio is 11.42:1, above the 4.5:1 needed for normal text. It also meets AAA (7:1).
What is the contrast ratio of #312e81 and #ffffff?
11.42:1, calculated with the WCAG 2.2 relative luminance formula. The ratio is truncated, not rounded, so it never shows a failing pair as passing.

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