What is the minimum acceptable color contrast ratio according to WCAG?

The Web Content Accessibility Guidelines (WCAG) provide specific recommendations for color contrast ratios to ensure text and user interface elements are accessible to people with visual impairments. The minimum acceptable color contrast ratios according to WCAG are as follows:

### **1. **Text and Background Contrast**

- **Normal Text:**
  - **Minimum Contrast Ratio:** 4.5:1
  - **Applicable to:** Text smaller than 18pt (or 14pt bold) and any other text that does not fall into the "large text" category.

- **Large Text:**
  - **Minimum Contrast Ratio:** 3:1
  - **Applicable to:** Text that is 18pt (or 14pt bold) and larger.

### **2. **User Interface Components and Graphical Objects**

- **UI Components (e.g., buttons, form fields):**
  - **Minimum Contrast Ratio:** 3:1
  - **Applicable to:** User interface components and their visible states, such as buttons, input fields, and icons.

- **Graphical Objects (e.g., charts, graphs):**
  - **Minimum Contrast Ratio:** 3:1
  - **Applicable to:** Graphical elements and visual representations of data that need to be distinguishable from their background.

### **3. **Additional Considerations**

- **Text Over Images:** If text is displayed over an image or patterned background, the contrast between the text and the background should meet the specified ratios, possibly requiring additional adjustments like overlays or background blurs to achieve sufficient contrast.
- **Interactive Elements:** Ensure that interactive elements like links and buttons meet the contrast requirements, as inadequate contrast can affect usability and accessibility.

### **Levels of Conformance**

- **Level AA (Minimum Level):** Meets the minimum contrast ratios outlined above.
- **Level AAA (Enhanced Level):** Some additional contrast requirements may be recommended for even greater accessibility, though specific ratio requirements beyond those for Level AA are not defined.

### **Summary**

The WCAG specifies a minimum color contrast ratio of 4.5:1 for normal text and 3:1 for large text and user interface components. These guidelines help ensure that text and interactive elements are sufficiently distinguishable from their backgrounds, improving readability and accessibility for users with visual impairments.