Colormapped
Color converter

RGB to CMYK Converter

Convert digital RGB values to a mathematical CMYK approximation.

This is a mathematical conversion, not a printer-profile color-management result.

What this tool does

RGB describes emitted screen light; CMYK describes amounts of cyan, magenta, yellow, and black in a subtractive print model. This tool performs a simple mathematical conversion, not ICC color management.

Enter the values in the calculator above and choose Calculate. The calculation runs in your browser; the inputs are not intentionally sent to a Colormapped application server.

How it works

  1. Normalize RGB channels to 0–1.
  2. Calculate K as 1 minus the largest normalized RGB channel.
  3. For non-black colors, derive C, M, and Y after removing the shared black component.
  4. Round C, M, Y, and K to percentages.

Worked example

Inputrgb(91, 92, 240)
Outputcmyk(62% 62% 0% 6%)

The numbers are a device-independent mathematical approximation. A real printer profile may choose different ink percentages for the same visual target.

When to use it

  • Estimate a starting CMYK breakdown from a screen color.
  • Understand roughly which process-ink channels dominate a color.
  • Prepare a quick non-color-managed reference before handing work to a print workflow.

Accuracy and limits

  • This is not a proofing or ICC-profile conversion.
  • Printed appearance depends on ink set, press/printer, paper, black generation, and profile.

Useful next steps

CMYK to RGB See how the rounded CMYK estimate maps back to screen channels. HEX to CMYK Start from a HEX design token instead of decimal RGB channels. CMYK vs RGB Understand why a mathematical conversion is not a press profile.