RGB to CMYK Converter

Convert RGB screen colors to CMYK print values instantly. Enter red, green and blue channels and get cyan, magenta, yellow and black percentages ready for print design.

Format: red, green, blue (each 0–255). Example: 21, 94, 239

Converted Values

HEX#155EEF
RGBrgb(21, 94, 239)
HSLhsl(215, 84%, 51%)
CMYKcmyk(91%, 61%, 0%, 6%)

What Is RGB to CMYK Conversion?

RGB to CMYK conversion translates the additive screen color model into the subtractive print color model. RGB uses three colored lights; CMYK uses four inks (cyan, magenta, yellow, black). Because print cannot reproduce all screen colors, the conversion is approximate — but the standard formula gives a solid starting point for print work.

How RGB to CMYK Works

rgb(21, 94, 239)
Normalized: R=0.082, G=0.369, B=0.937

K = 1 - max(R,G,B)  = 1 - 0.937 = 0.063 → 6%
C = (1-R-K)/(1-K)   = (0.918-0.063)/0.937 = 0.912 → 91%
M = (1-G-K)/(1-K)   = (0.631-0.063)/0.937 = 0.606 → 61%
Y = (1-B-K)/(1-K)   = (0.063-0.063)/0.937 = 0.000 → 0%

Result: cmyk(91%, 61%, 0%, 6%)

Why Convert RGB to CMYK?

  • Print projects: Brand colors need CMYK values before going to a printer.
  • Packaging: Production files must be in CMYK for standard offset printing.
  • Print-on-demand: Checking whether a screen color will reproduce acceptably.
  • Design documentation: Brand guides list both RGB and CMYK values for each color.

Common RGB Colors in CMYK

  • rgb(255, 0, 0) → cmyk(0%, 100%, 100%, 0%) — red
  • rgb(0, 0, 0) → cmyk(0%, 0%, 0%, 100%) — black
  • rgb(255, 255, 255) → cmyk(0%, 0%, 0%, 0%) — white
  • rgb(21, 94, 239) → cmyk(91%, 61%, 0%, 6%) — OmniColor blue

Gamut Limitations

Bright, saturated screen colors — especially vivid cyans, greens and blues — often shift noticeably when converted to CMYK. To keep printed output close to screen intent, choose colors with more moderate saturation, or use a spot color (Pantone) for critical brand elements. Always request a printed proof before full production runs.

Frequently Asked Questions