Contrast Checker
Check and improve color contrast effortlessly.
How does the Contrast Checker work?
This tool is based on the Web Content Accessibility Guidelines (WCAG), a set of internationally recognized recommendations designed to make digital content more accessible to everyone, including people with visual impairments, low vision, or color perception challenges. The WCAG standard, maintained by the World Wide Web Consortium (W3C), defines clear rules for evaluating whether the contrast between foreground and background colors is sufficient for comfortable and readable text.
Color contrast plays a critical role in user interface design. Insufficient contrast can make text difficult or even impossible to read, particularly in situations such as:
- Users browsing in bright sunlight or low-light environments
- People with partial color blindness or aging eyesight
- Small or thin fonts used in modern UI layouts
- High-density user interfaces, dashboards, and mobile screens
By using this checker, you ensure that text is accessible and usable in a wider range of real-world conditions and for a broader audience.
WCAG Contrast Levels Explained
WCAG defines two main levels of color contrast conformance: AA and AAA. Each level specifies a minimum contrast ratio depending on the size and weight of the text.
| WCAG Level | Normal Text | Large Text (≥ 18pt or ≥ 14pt bold) |
|---|---|---|
| AA | 4.5:1 | 3:1 |
| AAA | 7:1 | 4.5:1 |
Large text is defined as text 18pt (24px) or larger, or 14pt (18.6px) if bold.
Ratios are calculated using the relative luminance of each color, as defined in the WCAG formula.
Where does this standard come from?
The contrast requirements are part of the WCAG success criteria related to visual readability. These guidelines are often referenced in:
- International accessibility laws and regulations
- Government and public sector digital services
- Educational platforms and e-learning systems
- Corporate accessibility compliance policies
For more detailed documentation, see the WCAG specification on Wikipedia: Web Content Accessibility Guidelines.
Why does contrast matter?
Good color contrast improves:
- Text readability in all lighting conditions
- Accessibility for users with low vision or color blindness
- Usability across devices, including mobile screens and tablets
- Compliance for audits and legal accessibility requirements
- Conversion and user retention in digital products
Improving color contrast is one of the most cost-effective accessibility wins in UI/UX design.
How the contrast ratio is calculated
This tool uses the official WCAG formula, which evaluates the relative luminance between text color and background color:
Where:
- L1 is the luminance of the lighter color
- L2 is the luminance of the darker color
The result is always a number between 1:1 (no contrast) and 21:1 (maximum contrast)
The higher the ratio, the easier it is to distinguish content.
Practical examples
| Text & Background | Contrast Result |
|---|---|
| White on #29ABE2 (this page default) | Meets AA for large text, may vary for normal text |
| Light gray on white | Often fails AA and AAA |
| Black on white | Passes AAA for all sizes |
When choosing brand colors, UI themes, buttons, and headings, always validate contrast before publishing.
Recommended usage for designers and developers
Use this checker when working on:
- UI/UX design systems and color palettes
- Web and mobile typography
- Front-End frameworks (CSS, Tailwind, Chakra, Material UI, etc.)
- Dashboards, charts, and analytics components
- Email templates, marketing pages, e-commerce, and documentation
Ensuring contrast early in the design process reduces redesign costs and improves accessibility compliance.
How to Use the Tool
- Enter a foreground and background color using the HEX input fields or the color pickers.
- Check the contrast ratio and the AA/AAA compliance grades in real-time.
- Use the live preview and text size toggle to see how it looks.