RGB to CMYK converter
Move the red, green and blue sliders and read cyan, magenta, yellow and key instantly. HueKit also shows hex and HSL so you have every format at once.
Converting RGB to CMYK
RGB is additive: red, green and blue light stack up toward white. CMYK is subtractive: cyan, magenta, yellow and key ink strip light away from a white page. To bridge the two, HueKit first pulls out the key from the brightest of the three RGB channels, since that channel is the one ink cannot darken any further without going past black. Cyan, magenta and yellow are then set from how far red, green and blue trail behind that peak, once the key portion is divided back out.
Because RGB and CMYK cover different gamuts, the conversion is a useful approximation rather than a lossless swap. It is exact enough for previewing how a screen color will translate to ink, which is the job most designers need it to do.
When you need this jump
This conversion comes up whenever a color starts life on screen, picked in RGB or hex, and has to travel to a print brief. Set the sliders to your brand color and read off cyan, magenta, yellow and key as a starting point for a press file. For the reverse trip, use the CMYK to RGB converter, and the full color converter covers every model at once.
Frequently asked questions
How do I convert RGB to CMYK?
HueKit first finds the key, or black, as one minus the strongest of the three RGB channels. Cyan, magenta and yellow then each measure how far their own channel falls short of that peak, scaled against the remaining range once the key is removed.
Why does pure black come out as 0, 0, 0, 100 instead of full ink?
When red, green and blue are all zero, the key channel alone reaches 100 percent and cyan, magenta and yellow drop to zero. Loading up all four inks would only muddy pure black, so the formula routes it through key alone.
Is this the exact CMYK a printer will use?
It is the standard device-independent formula, accurate for on-screen previews. A real print shop converts through an ICC profile tuned to their paper and ink, which shifts the numbers slightly. Treat this result as a close approximation, not a press-ready separation.