RGB to CMYK converter
Enter the red, green and blue values and get CMYK values as a starting point for print artwork.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter red (r), green (g) and blue (b).
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
K = 1 - max(R/255, G/255, B/255), C = (1 - R/255 - K) / (1 - K), M = (1 - G/255 - K) / (1 - K), Y = (1 - B/255 - K) / (1 - K); pure black gives K = 1 and zero for the rest.
Example
Inputs: Red (R) = 30, Green (G) = 144, Blue (B) = 255. Result: CMYK code: cmyk(88.2%, 43.5%, 0%, 0%); Cyan (C): 88.2 %; Magenta (M): 43.5 %.
Limits and caveats
- CMYK uses the naive device-independent formula with no ICC profile, so it will not match a specific press, paper or ink.
- Values in the code are rounded to one decimal, so converting back can shift an RGB channel by 1.
- All values are treated as sRGB, the default web color space, not Display P3 or Adobe RGB.
Questions about this tool
Why is white 0% in every CMYK channel?
Printing starts from white paper, so white simply means no ink at all.
What range do the RGB fields accept?
Each channel takes a whole number from 0 to 255, where 0 means none of that light and 255 means full intensity.
Will these CMYK values match my print shop?
Not necessarily. This is a plain formula that knows nothing about paper or ink; for accurate print, convert in your design app with the ICC profile your printer gives you.