Level AAA

AAA raises the contrast bar from 4.5:1 to 7:1 for normal text, targeting legibility for users with roughly 20/80 vision

1.4.6 Contrast (Enhanced)

In Plain Language

1.4.6 Contrast (Enhanced) raises the contrast threshold from the 1.4.3 Contrast (Minimum) Level AA bar of 4.5:1 to 7:1 for normal text, and from 3:1 to 4.5:1 for large text[1]. Large text is the same threshold as 1.4.3: 18pt or larger, or 14pt or larger when bold.

The formula is identical to 1.4.3 -- relative luminance of foreground and background computed via the WCAG 2 contrast algorithm[2]. Only the passing ratio changes. The same exceptions carry over: incidental text, logotypes, and inactive UI components are out of scope.

Why It Matters

  • The 7:1 ratio is calibrated to approximate standard-print legibility for users with roughly 20/80 visual acuity, the same way 4.5:1 approximates it for 20/40 acuity at Level AA[1]. Each step down in acuity requires roughly 1.5x more contrast to recover the same reading performance.
  • Users with age-related macular degeneration, advanced cataracts, diabetic retinopathy, and other conditions that reduce contrast sensitivity fall into this range without necessarily running a screen magnifier, high-contrast OS mode, or other assistive tech. The enhanced ratio is what lets them read body copy with only their default browser settings.
  • The 7:1 threshold also absorbs real-world degradation that the AA minimum does not: glare on mobile screens in sunlight, aging LCD panels, OS-level brightness reduction, and dark-mode theming that compresses luminance range. Text that just barely clears 4.5:1 in a controlled lab often fails in the wild.
  • 1.4.6 is Level AAA and is not required for AA conformance[3]. It is a forward-looking target for programs aiming beyond the legal minimum -- gov.uk, public-sector procurement with enhanced accessibility clauses, and design systems that want headroom above the AA floor.

Examples

Do: Normal text at 7:1 or above

Account Settings

Review and update your personal information, notification preferences, and security options below.

Ratio: #333 on #ffffff = 12.6:1 ✔ (7:1 required for AAA)

<h3 style="color: #1e2a32;">Account Settings</h3>
<p style="color: #333;">
  Review and update your personal information.
</p>
<!-- #1e2a32 on #fff = 14.8:1 (headings) -->
<!-- #333 on #fff = 12.6:1 (body text) -->
<!-- Both exceed the 7:1 AAA threshold -->
Don't: Text that passes AA but fails AAA

Account Settings

This medium-gray text passes the AA 4.5:1 threshold but falls short of the AAA 7:1 requirement.

Ratio: #6b7f8e on #ffffff = 3.9:1 ✘ (needs 7:1 for AAA)

<!-- Passes AA 4.5:1 but FAILS AAA 7:1 -->
<h3 style="color: #5a6f7e;">Account Settings</h3>
<p style="color: #6b7f8e;">
  This medium-gray text is 3.9:1 -- not enough for AAA.
</p>
<!-- #6b7f8e on #fff = 3.9:1 (fails both AA and AAA) -->
Do: Large text at 4.5:1 or above

Our Programs

Large text (24px): #4b5e6d on #ffffff = 5.7:1 ✔ (4.5:1 required for AAA large text)

Don't: Large text below 4.5:1

Our Programs

Large text (24px): #d4842a on #ffffff = 3.5:1 ✘ (passes AA 3:1, fails AAA 4.5:1)

How to Fix It

  1. Recompute your palette against 7:1 and 4.5:1. The WCAG 2 contrast formula is the same as for 1.4.3 -- only the passing thresholds move. Any color pair at the 4.5:1 AA floor will fail 1.4.6 for normal text.
  2. Push body text darker. On white backgrounds, #595959 hits exactly 7:1; anything lighter fails. #333 sits at 12.6:1 and carries comfortable headroom. Medium grays in the #666-#777 range pass AA but fail AAA.
  3. Treat large text as a separate token. The 4.5:1 threshold for AAA large text is identical to the AA threshold for normal text, so a color that just clears AA normal-text can only be reused for AAA large-text, not AAA body.
  4. Watch the exceptions. Logotypes and incidental text are out of scope, same as 1.4.3. Inactive (disabled) controls are also exempt -- but if a control looks disabled and is not, 1.4.6 applies and the low-contrast gray will fail.
  5. Pair with 1.4.11 Non-text Contrast. Meeting 1.4.6 on text does not cover icons, form borders, or focus indicators -- those have their own 3:1 requirement under 1.4.11 and are untouched by the AAA text bar.

References

  1. [1] W3C (2023). Understanding Success Criterion 1.4.6: Contrast (Enhanced). W3C, Accessed 2026-04-07. https://www.w3.org/WAI/WCAG22/Understanding/contrast-enhanced.html ↩ ↩
  2. [2] W3C (2023). Understanding Success Criterion 1.4.3: Contrast (Minimum). W3C, Accessed 2026-04-07. https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html ↩
  3. [3] W3C (2023). Web Content Accessibility Guidelines (WCAG) 2.2. W3C, Accessed 2026-04-07. https://www.w3.org/TR/WCAG22/ ↩