Color contrast calculator
Color contrast calculator with strict validation and deterministic output.
Runs in your browserEvery computation happens in your browser — your data never leaves this device.
Input
Result
Deterministic output ready to copy.
Enter a value to see the result
What this tool does
- Frontend styling and color checks
- Development and learning
Example
Input
#000000;#ffffff
Output
contrast ratio: 21.00:1
The result follows explicit color or CSS rules.
Frequently asked questions
What input is supported?
Enter the color, number, or CSS parameter described by the tool; invalid formats are rejected.
Can I copy the result?
The deterministic plain-text result is ready to paste into code.
Are color calculations reliable?
Conversions use standard RGB, HSV, HSL, CMYK, or WCAG formulas with documented rounding.
Keywords：颜色匹配度计算器Color contrast calculatorcolor_diffCSS颜色converter