Check if your text and background color combination meets WCAG AA and AAA accessibility standards. See contrast ratio and live preview.
Text Color
Background Color
The quick brown fox jumps over the lazy dog
Normal body text at 16px. Accessibility matters for everyone.
Small text at 12px — often used for captions, footnotes, and labels.
Contrast Ratio
—
:1
WCAG AA — Normal Text
—
Requires ≥ 4.5:1
WCAG AA — Large Text
—
Requires ≥ 3:1
WCAG AAA — Normal Text
—
Requires ≥ 7:1
WCAG AAA — Large Text
—
Requires ≥ 4.5:1
Level
Text Size
Minimum Ratio
Result
WCAG AA
Normal text (< 18pt / 14pt bold)
4.5 : 1
—
WCAG AA
Large text (≥ 18pt / 14pt bold)
3 : 1
—
WCAG AAA
Normal text
7 : 1
—
WCAG AAA
Large text
4.5 : 1
—
About Color Contrast Checker
The Web Content Accessibility Guidelines (WCAG) define minimum contrast ratios for text to ensure readability for people with visual impairments. This tool calculates the relative luminance of two colors and computes the contrast ratio according to the WCAG 2.1 formula.
WCAG Contrast Levels Explained
AA (minimum) — 4.5:1 for normal text, 3:1 for large text (≥ 18pt or bold ≥ 14pt). Required for most websites. AAA (enhanced) — 7:1 for normal text, 4.5:1 for large text. Recommended for the best accessibility.
Frequently Asked Questions
WCAG stands for Web Content Accessibility Guidelines. They are published by the W3C and define how to make web content more accessible to people with disabilities, including those with low vision or color blindness.
WCAG defines large text as text that is at least 18pt (24px) in normal weight, or at least 14pt (18.67px) in bold weight. Headings typically qualify as large text; body copy usually does not.
The contrast ratio is (L1 + 0.05) / (L2 + 0.05), where L1 is the relative luminance of the lighter color and L2 is the relative luminance of the darker color. Relative luminance is computed from linearized RGB values using the WCAG 2.1 formula.
AA is the minimum standard required by most accessibility laws and guidelines (including WCAG 2.1 Level AA compliance). AAA is the enhanced level and is recommended but not always required. Aim for AA as a baseline, and AAA where feasible.
About Color Contrast Checker
Color contrast is a critical part of web accessibility. The WCAG (Web Content Accessibility Guidelines) require a minimum contrast ratio between text and background colors so that content is readable by users with low vision or color blindness.
How to Use
Enter or pick your Foreground Color (text color) using the color picker or hex input.
Enter or pick your Background Color.
The Contrast Ratio and WCAG pass/fail results update instantly.
Check the preview panel to see how your color combination looks at normal and large text sizes.
How It Works
The tool calculates relative luminance for each color using the WCAG formula, then computes the contrast ratio as (L1 + 0.05) / (L2 + 0.05), where L1 is the lighter color's luminance. Results are compared against the WCAG 2.1 thresholds for AA (4.5:1 normal, 3:1 large) and AAA (7:1 normal, 4.5:1 large).
Example
Black text (#000000) on white background (#FFFFFF): contrast ratio = 21:1 — passes all WCAG levels. Dark grey (#595959) on white passes AA but not AAA for normal text.
Frequently Asked Questions
WCAG (Web Content Accessibility Guidelines) is a set of international standards for web accessibility published by the W3C. WCAG 2.1 is the current widely adopted version, with levels A, AA, and AAA. Most organizations target AA compliance.
WCAG defines large text as 18pt (24px) or larger for normal weight, or 14pt (approximately 18.67px) or larger for bold text. Large text has a lower contrast requirement (3:1 for AA) because it is easier to read.
Most web projects aim for WCAG AA compliance, which is legally required in many jurisdictions. AAA is the highest level and can be difficult to achieve while maintaining attractive design, so it is typically a stretch goal.
This tool checks text contrast only. Non-text contrast (for icons, form controls, etc.) also has WCAG requirements (3:1 minimum for AA) but requires visual inspection rather than a simple ratio check.