Provide the starting value
Calculate the contrast ratio for one foreground/background HEX pair and inspect text and UI pass/fail criteria implemented by the checker.
WCAG Color Contrast Checker
Calculate the contrast ratio for one foreground/background HEX pair and inspect text and UI pass/fail criteria implemented by the checker.
The verified workflow runs in the browser. Files and color values stay in the page unless a control explicitly opens a network URL.
Large Text (24px+)
Normal text at 16px. The quick brown fox jumps over the lazy dog.
Small text at 14px for fine print and captions.
Contrast Ratio
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Direct answer
Calculate the contrast ratio for one foreground/background HEX pair and inspect text and UI pass/fail criteria implemented by the checker. A passing pair does not make an entire page WCAG-conformant or legally compliant. The current inputs do not composite translucent foregrounds over the background.
What this tool does
Calculate the contrast ratio for one foreground/background HEX pair and inspect text and UI pass/fail criteria implemented by the checker. Check a text/background or component/background pair, then verify typography, states, focus and non-color cues in the real interface.
Verified capabilities
Adjust the relevant controls
Relative luminance is calculated from linearized sRGB channels, then compared with 4.5:1, 3:1 and 7:1 thresholds. Suggested fixes search HSL lightness while keeping hue and saturation.
Check the accuracy boundary
A passing pair does not make an entire page WCAG-conformant or legally compliant. The current inputs do not composite translucent foregrounds over the background. Compare the result with the intended destination before reusing it.
When to use it
- Check a text/background or component/background pair, then verify typography, states, focus and non-color cues in the real interface.
- Relative luminance is calculated from linearized sRGB channels, then compared with 4.5:1, 3:1 and 7:1 thresholds. Suggested fixes search HSL lightness while keeping hue and saturation. In “When to use it 2”, apply this specifically to WCAG Color Contrast Checker.
- Check a text/background or component/background pair, then verify typography, states, focus and non-color cues in the real interface. Use the first related tool to continue from the output of WCAG Color Contrast Checker without changing locale.
How to use the tool
Provide the starting value
Calculate the contrast ratio for one foreground/background HEX pair and inspect text and UI pass/fail criteria implemented by the checker. In “How to use the tool: Provide the starting value”, apply this specifically to WCAG Color Contrast Checker.
Adjust the relevant controls
Relative luminance is calculated from linearized sRGB channels, then compared with 4.5:1, 3:1 and 7:1 thresholds. Suggested fixes search HSL lightness while keeping hue and saturation. In “How to use the tool: Adjust the relevant controls”, apply this specifically to WCAG Color Contrast Checker.
Review and continue
Check a text/background or component/background pair, then verify typography, states, focus and non-color cues in the real interface. In “How to use the tool: Review and continue”, apply this specifically to WCAG Color Contrast Checker.
Check the accuracy boundary
A passing pair does not make an entire page WCAG-conformant or legally compliant. The current inputs do not composite translucent foregrounds over the background. Compare the result with the intended destination before reusing it. Review the stated limitation before treating the result as a production or accessibility decision.
Controls explained
Provide the starting value
Calculate the contrast ratio for one foreground/background HEX pair and inspect text and UI pass/fail criteria implemented by the checker. In “Controls explained: Provide the starting value”, apply this specifically to WCAG Color Contrast Checker.
Adjust the relevant controls
Relative luminance is calculated from linearized sRGB channels, then compared with 4.5:1, 3:1 and 7:1 thresholds. Suggested fixes search HSL lightness while keeping hue and saturation. In “Controls explained: Adjust the relevant controls”, apply this specifically to WCAG Color Contrast Checker.
How the result is produced
Relative luminance is calculated from linearized sRGB channels, then compared with 4.5:1, 3:1 and 7:1 thresholds. Suggested fixes search HSL lightness while keeping hue and saturation. In “How the result is produced”, apply this specifically to WCAG Color Contrast Checker.
Accuracy and limitations
- A passing pair does not make an entire page WCAG-conformant or legally compliant. The current inputs do not composite translucent foregrounds over the background.
- Clipboard, file decoding, download and permission-based controls follow the capabilities of the current browser.
Processing and privacy
The verified workflow runs in the browser. Files and color values stay in the page unless a control explicitly opens a network URL.
Practical tips
- Start from a known sample, then change one control at a time so the effect remains explainable.
- Review the stated limitation before treating the result as a production or accessibility decision.
Troubleshooting
The input or action does not work
Check the displayed range or file requirement, reset the tool, then retry with a smaller or browser-supported input. Permission-based controls may need a secure context.
Accuracy and limitations
A passing pair does not make an entire page WCAG-conformant or legally compliant. The current inputs do not composite translucent foregrounds over the background. In “Troubleshooting: Accuracy and limitations”, apply this specifically to WCAG Color Contrast Checker.
Check the accuracy boundary
A passing pair does not make an entire page WCAG-conformant or legally compliant. The current inputs do not composite translucent foregrounds over the background. Reset the tool and retry with a known supported value before reporting an algorithm error.
Questions about this tool
What does WCAG Color Contrast Checker do?
Calculate the contrast ratio for one foreground/background HEX pair and inspect text and UI pass/fail criteria implemented by the checker. In “What does WCAG Color Contrast Checker do?”, apply this specifically to WCAG Color Contrast Checker.
What is the most important limitation?
A passing pair does not make an entire page WCAG-conformant or legally compliant. The current inputs do not composite translucent foregrounds over the background. In “What is the most important limitation?”, apply this specifically to WCAG Color Contrast Checker.
Where is the data processed?
The verified workflow runs in the browser. Files and color values stay in the page unless a control explicitly opens a network URL. In “Where is the data processed?”, apply this specifically to WCAG Color Contrast Checker.
What input should I prepare for WCAG Color Contrast Checker?
Calculate the contrast ratio for one foreground/background HEX pair and inspect text and UI pass/fail criteria implemented by the checker. Calculate the contrast ratio for one foreground/background HEX pair and inspect text and UI pass/fail criteria implemented by the checker.
What should I verify before using the result from WCAG Color Contrast Checker?
A passing pair does not make an entire page WCAG-conformant or legally compliant. The current inputs do not composite translucent foregrounds over the background. Compare the result with the intended destination before reusing it. In “What should I verify before using the result from WCAG Color Contrast Checker?”, apply this specifically to WCAG Color Contrast Checker.
Which workflow can follow WCAG Color Contrast Checker?
Use the first related tool to continue from the output of WCAG Color Contrast Checker without changing locale. Check a text/background or component/background pair, then verify typography, states, focus and non-color cues in the real interface.
Continue your color workflow
Check a text/background or component/background pair, then verify typography, states, focus and non-color cues in the real interface. In “Continue your color workflow”, apply this specifically to WCAG Color Contrast Checker.
Continue with a related tool
Use the first related tool to continue from the output of WCAG Color Contrast Checker without changing locale.
Color Blindness Simulator for Design Accessibility