Toolsloft

RGB to CMYK Converter

Convert RGB screen colors to CMYK print values (cyan, magenta, yellow, key). Free, instant, and private.

Independently verified for accuracy

Calculator by Toolsloft ↗
CMYK
cmyk(75%, 50%, 0%, 20%)

Convert an RGB screen color to CMYK, the four-ink model used for print. Enter red, green, and blue from 0 to 255 and read the cyan, magenta, yellow, and key (black) percentages. Use it to translate a web color into something a printer can reproduce.

How this is calculated

Black (key) is one minus the largest normalized channel, then cyan, magenta, and yellow are the remaining ink each channel needs once black is removed. This is the standard device-independent RGB to CMYK conversion.

How to use

  1. Enter the red, green, and blue values, each from 0 to 255.
  2. The CMYK percentages appear below as you type.
  3. Use the values as a starting point for your print file.

Examples

  • 51, 102, 204: cmyk(75%, 50%, 0%, 20%)
  • 255, 0, 0: cmyk(0%, 100%, 100%, 0%)

FAQ

Will my printer match these exact values?
Not exactly. This is the standard math conversion, but real printing depends on the ink, paper, and color profile. Treat the result as a close starting point, not a guaranteed match.
Why is black called key?
The K in CMYK stands for key, the black plate that carries most of the detail. Using black ink instead of layering cyan, magenta, and yellow saves ink and gives cleaner shadows.
Why is CMYK zero for pure white?
White is the paper itself, so no ink is needed. All four channels are 0 percent.

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