Goal
Provide enhanced text contrast for users who need very high readability.
Success Criterion · WCAG 1.4.6
Contrast (Enhanced)
The visual presentation of text and images of text has a contrast ratio of at least 7:1, except for large text (at least 4.5:1), incidental text, and logotypes.
Level AAAWCAG 2.0Perceivable1.4 · Distinguishable
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What to do
Meet contrast ratios: at least 7:1 for normal text and 4.5:1 for large text (with defined exceptions).
Why it matters
Some users need stronger contrast than Level AA provides, especially with low vision or contrast sensitivity loss.
Success criterion
What WCAG 1.4.6 requires
Summarized directly from the official Understanding document so teams can quote the requirement accurately.
The visual presentation of text and images of text has a contrast ratio of at least 7:1, except for large-scale text, incidental text, and logotypes.
Intent
Why WCAG created this requirement
- Higher contrast improves readability for users with significant low vision.
- AAA targets content aiming for the highest accessibility outcomes.
- The same exceptions as 1.4.3 apply (incidental text, logotypes, and large text thresholds).
Benefits
Who gains when you pass
- Users with low vision and reduced contrast sensitivity can read content more comfortably.
- Users in challenging viewing conditions (glare, low-quality screens) benefit from improved legibility.
- Older users and users with cataracts or glaucoma benefit from stronger contrast.
- Users can rely less on custom styles or high-contrast overrides.
Why it matters
User impact when this criterion fails
Summaries drawn from the Understanding document help you socialize impact statements with product stakeholders.
Content that meets AA but not AAA may remain difficult to read for some users with low vision.
Users may need to use custom contrast settings or abandon reading long passages.
Exception guidelines
Use the WCAG 1.4.6 exceptions correctly
Document the rationale for each exception and note which alternative support you provide.
Large-scale text
Large text requires less contrast because of increased legibility.
Requirement
At least 4.5:1 for large-scale text.
Incidental text
Decorative or incidental text not intended to be read is exempt.
Requirement
If not intended to be read, it may be exempt.
Logotypes
Text that is part of a logo or brand mark is exempt.
Requirement
Logotypes do not need to meet contrast ratio requirements.
Overview
This AAA criterion strengthens 1.4.3. Normal text must be at least 7:1 and large text at least 4.5:1. Decorative/incidental text and logotypes are exempt.
- Aim for a token system that includes AAA-safe pairs for common UI text and surfaces.
- Check contrast across states (hover/focus) and for text on gradients/images.
- Consider increasing font weight/size in addition to contrast for comfort, but contrast is still required.
Reference: All summaries and highlights originate from Understanding WCAG 1.4.6 and the W3C quick reference.
Fast facts
- Conformance level
- Level AAA
- WCAG version introduced
- WCAG 2.0
- Principle
- Perceivable
- Guideline
- 1.4 · Distinguishable
Examples
Make success tangible for teams
Share pass/fail snapshots to coach designers, engineers, QA, and content authors.
Normal text
Pass
Very dark text on white (≥ 7:1).
Fail
Medium gray on white that is ~5:1 (AA but not AAA).
Large text
Pass
Large heading text at 4.5:1 or higher.
Fail
Large heading at 3.2:1 (AA large text but not AAA).
Overlay text
Pass
Overlay uses opaque backplate to maintain 7:1 contrast.
Fail
Semi-transparent overlay causes variable contrast below 7:1.
Evidence to keep
Document conformance decisions
Capture artifacts for VPATs, procurement reviews, and regression testing.
- Maintain a palette list of AAA-approved text/background pairs with measured ratios.
- Record decisions where AAA is not feasible and which areas remain AA-only.
Official resources
Deep dives and supporting material
Keep these links handy when writing acceptance criteria or responding to audits.
Understanding 1.4.6
Official W3C interpretation, techniques, and intent for Contrast (Enhanced).
Quick Reference 1.4.6
Filterable list of sufficient techniques and failures.
Technique G17
Ensuring a contrast ratio of at least 7:1 for normal text.
Technique G18
Ensuring a contrast ratio of at least 4.5:1 for normal text (baseline reference).
Failure F24
Failure due to insufficient contrast between text and background.
Implementation checklist
Capture progress and blockers
- Identify content areas targeting AAA compliance.
- Update color tokens to provide 7:1 contrast pairs for normal text.
- Verify large text meets 4.5:1.
- Review states (hover/focus/active) for contrast regressions.
- Avoid translucent text overlays that reduce effective contrast.
- Document logotype/incidental text exceptions where used.
Testing ideas
Prove conformance with evidence
- Measure contrast for representative UI text and surfaces; confirm 7:1 or 4.5:1 thresholds.
- Check text on images/gradients at multiple points.
- Test both light and dark themes, including elevated surfaces and overlays.
- Verify error/help text also meets thresholds (not just primary content).
Related success criteria
More from Distinguishable (1.4)
WCAG 1.4.1Use of ColorLevel AWCAG 1.4.2Audio ControlLevel AWCAG 1.4.3Contrast (Minimum)Level AAWCAG 1.4.4Resize TextLevel AAWCAG 1.4.5Images of TextLevel AAWCAG 1.4.7Low or No Background AudioLevel AAAWCAG 1.4.8Visual PresentationLevel AAAWCAG 1.4.9Images of Text (No Exception)Level AAAWCAG 1.4.10ReflowLevel AAWCAG 1.4.11Non-text ContrastLevel AAWCAG 1.4.12Text SpacingLevel AAWCAG 1.4.13Content on Hover or FocusLevel AA