Free tool
WCAG color contrast checker
Check whether a text color and a background color meet the contrast ratios in the Web Content Accessibility Guidelines (WCAG) 2.1. The calculation runs in your browser. We do not upload your colors or store them on our server. After an accepted check, a share link keeps the colors in the URL fragment on your device.
Result
Contrast ratio:
| Check | Needs | Result |
|---|---|---|
| 1.4.3 Contrast (Minimum), Level AA: normal text | 4.5:1 | |
| 1.4.3 Contrast (Minimum), Level AA: large text | 3:1 | |
| 1.4.6 Contrast (Enhanced), Level AAA: normal text | 7:1 | |
| 1.4.6 Contrast (Enhanced), Level AAA: large text | 4.5:1 | |
| 1.4.11 Non-text Contrast, Level AA: user-interface components and graphical objects | 3:1 | |
| Technique G183: link color versus surrounding text () | 3:1 |
The link keeps the colors after the # in the address. That part of a link is not sent to our server when the page loads.
Limits of this result
- This checks one or two color pairs you typed. It is not a page audit and not a WCAG conformance claim for any website.
- It does not account for transparency, background images, gradients, text shadows or anti-aliasing, which can change contrast on a real page (see Understanding 1.4.3).
- Large text means at least 18 point (about 24 CSS px) or 14 point bold (about 18.5 CSS px), per Understanding 1.4.3. Unusual or very thin fonts may still be hard to read.
- Logos and incidental or inactive text have exceptions in 1.4.3; this tool does not decide those cases.
- ADA Title II for state and local government web content adopts WCAG 2.1 Level AA. 1.4.3 and 1.4.11 are AA. 1.4.6 is AAA and is not required by that AA bar. This is general information, not legal advice.
- The ratio shown is cut to two decimals, never rounded up. Pass or fail uses the full, unrounded value.
Normal body text in the chosen colors.
Large text in the chosen colors
Surrounding paragraph text in its own color.
This tool runs in your browser. The colors you enter and the result stay on your device; this tool does not send them to ValleyFill or an AI provider. For Terms acceptance, we store only the acceptance time, tool path and Terms version in this tab’s session storage; that record is not sent to ValleyFill. Accessibility display preferences are stored separately in your browser. Normal page requests still reach our host, and our Privacy Policy describes server logs and anonymous visit counts. Don’t paste passwords or sensitive personal information. This is a free automated tool, not legal advice, certification or a guarantee of accessibility or compliance.
What the ratio means
WCAG defines contrast as a ratio of relative luminance, from 1:1 (the same color twice) to 21:1 (black on white). The formula is (L1 + 0.05) / (L2 + 0.05), using the sRGB relative-luminance definition published in WCAG 2.1. Hue is not a separate factor: the test is about light versus dark, which is what many people with low vision or color vision deficiency need. Source: Understanding Success Criterion 1.4.3 and the WCAG 2.1 contrast-ratio definition.
Thresholds this tool reports
- Normal text, Level AA (1.4.3): at least 4.5:1. Source: WCAG 2.1 Success Criterion 1.4.3.
- Large text, Level AA (1.4.3): at least 3:1. Large text is at least 18 point, or 14 point if bold (about 24px and 18.5px in CSS). Source: Understanding 1.4.3.
- Normal text, Level AAA (1.4.6): at least 7:1. Large text at AAA is 4.5:1. Source: WCAG 2.1 Success Criterion 1.4.6.
- User-interface components and graphical objects, Level AA (1.4.11): at least 3:1 against adjacent colors. Source: WCAG 2.1 Success Criterion 1.4.11.
- Link color versus surrounding text: when links are not always underlined, WCAG technique G183 documents a 3:1 contrast between the link color and the surrounding text, in addition to meeting 1.4.3 against the background. Source: G183.
WCAG says computed ratios should not be rounded when you compare them to a threshold: 4.499:1 does not meet 4.5:1. Source: Understanding 1.4.3.
How this relates to Title II
In April 2024 the U.S. Department of Justice amended its Title II regulation so that state and local government web content and mobile apps must meet WCAG 2.1 Level AA. The compliance dates, later extended by one year, are 26 April 2027 for public entities with a total population of 50,000 or more, and 26 April 2028 for those under 50,000 and for special district governments. Sources: ADA.gov fact sheet on the 2024 web rule and the Federal Register extension.
Because Title II points at Level AA, Success Criteria 1.4.3 and 1.4.11 are in that bar. Success Criterion 1.4.6 is Level AAA and is not required by an AA-only rule. This page is general information, not legal advice. Confirm your obligations with your counsel.
What this tool cannot do
It checks the colors you typed, not a live web page. Background images, transparency, gradients and font smoothing can all change what someone sees. Logos and purely decorative or inactive text have exceptions in 1.4.3. Meeting a ratio here is not a certification, an audit, or a statement that a site conforms to WCAG.
A free Title II Snapshot looks at basic signals on a public body’s own pages. A plain-language checker estimates reading level for text you paste.
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