Goal
Make text readable by ensuring sufficient contrast between text and its background.
Success Criterion · WCAG 1.4.3
Contrast (Minimum)
The visual presentation of text and images of text has a contrast ratio of at least 4.5:1, except for large text (at least 3:1), incidental text, and logotypes.
Level AAWCAG 2.0Perceivable1.4 · Distinguishable
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What to do
Meet contrast ratios: at least 4.5:1 for normal text and 3:1 for large text (with defined exceptions).
Why it matters
Low contrast makes text hard to read for many people, including users with low vision and color vision deficiencies.
Success criterion
What WCAG 1.4.3 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 4.5:1, except for large-scale text, incidental text, and logotypes.
Intent
Why WCAG created this requirement
- Contrast requirements ensure readability for users with low vision and in varied viewing conditions.
- Applies to text and images of text across all UI states (default, hover, focus, disabled when applicable).
- Exceptions exist for purely decorative/incidental text and branding/logotypes.
Benefits
Who gains when you pass
- Low vision users can read content without needing extreme zoom or custom themes.
- Users with color vision deficiencies can distinguish text from background more reliably.
- Mobile users in glare or bright sunlight can read content more easily.
- Older users benefit from improved legibility as contrast sensitivity declines with age.
Why it matters
User impact when this criterion fails
Summaries drawn from the Understanding document help you socialize impact statements with product stakeholders.
Users may be unable to read instructions, labels, or error messages due to low contrast.
Critical UI text (buttons, form labels) becomes effectively invisible for some users.
Users may make mistakes or abandon tasks when they cannot read content reliably.
Exception guidelines
Use the WCAG 1.4.3 exceptions correctly
Document the rationale for each exception and note which alternative support you provide.
Large-scale text
Large text has a lower minimum contrast requirement because it is easier to read.
Requirement
At least 3:1 for large-scale text.
Incidental text
Text that is purely decorative or incidental does not need to meet contrast.
Requirement
If the text is 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
Text must have enough contrast against its background to be readable. For normal-sized text, the minimum is 4.5:1. For large text (18pt regular or 14pt bold and above), the minimum is 3:1. Incidental or decorative text and logotypes are exempt.
- Measure contrast ratio between the text color and its background color at the point of rendering.
- Large-scale text has a lower threshold (3:1) but must meet the definition of “large.”
- If text sits on gradients/images, ensure contrast is sufficient across the entire area.
- Placeholder text should also be readable; avoid very low-contrast placeholders.
- Disabled text may still need adequate contrast if it conveys essential information.
Reference: All summaries and highlights originate from Understanding WCAG 1.4.3 and the W3C quick reference.
Fast facts
- Conformance level
- Level AA
- 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.
Body text
Pass
Dark gray (#111827) text on white background (≥ 4.5:1).
Fail
Light gray text on white (e.g., #9CA3AF on #FFFFFF) for body copy.
Button label
Pass
White button text on indigo background with ≥ 4.5:1 contrast.
Fail
White text on pale yellow background with < 4.5:1 contrast.
Text on image
Pass
Text placed on a semi-opaque overlay ensuring consistent contrast.
Fail
Text placed directly on a photo where parts of the text disappear.
Evidence to keep
Document conformance decisions
Capture artifacts for VPATs, procurement reviews, and regression testing.
- Maintain a palette of approved text/background pairs with measured ratios.
- Document which components are “large text” and why (font size/weight).
- Capture evidence screenshots for key templates and error states.
Official resources
Deep dives and supporting material
Keep these links handy when writing acceptance criteria or responding to audits.
Understanding 1.4.3
Official W3C interpretation, techniques, and intent for Contrast (Minimum).
Quick Reference 1.4.3
Filterable list of sufficient techniques and failures.
Technique G18
Ensuring a contrast ratio of at least 4.5:1 for normal text.
Technique G145
Ensuring a contrast ratio of at least 3:1 for large-scale text.
Failure F24
Failure due to insufficient contrast between text and background.
Implementation checklist
Capture progress and blockers
- Define accessible color tokens for text, backgrounds, and interactive states.
- Check contrast for body text, headings, form labels, helper text, and error messages.
- Verify contrast for text on buttons, chips, badges, and navigation elements.
- Avoid placing text directly over busy images; use overlays or solid backplates.
- Test contrast in both light and dark themes and in all states (hover/focus/disabled).
- Document exceptions (logos, incidental text) and ensure they are truly non-essential.
Testing ideas
Prove conformance with evidence
- Use a contrast checker to measure ratios for representative UI states.
- Verify normal text meets 4.5:1 and large text meets 3:1.
- Check text on gradients, images, and translucent overlays at multiple points.
- Test with OS high-contrast or forced-colors modes where applicable.
- Spot-check with users or QA at 200% zoom and on mobile in bright conditions.
Related success criteria
More from Distinguishable (1.4)
WCAG 1.4.1Use of ColorLevel AWCAG 1.4.2Audio ControlLevel AWCAG 1.4.4Resize TextLevel AAWCAG 1.4.5Images of TextLevel AAWCAG 1.4.6Contrast (Enhanced)Level AAAWCAG 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