CMYK Color Converter

Convert between CMYK (print) and RGB/Hex (screen) color values with visual swatch comparison.

Tested tool guide Tested browser tools Checked August 16, 2026

What CMYK Color Converter does, with a checked example

CMYK Color Converter translates cyan, magenta, yellow, and black percentages into RGB channel values and Hex notation, or converts an RGB or Hex color back to CMYK percentages. It also provides swatches for comparing the entered and converted colors on screen. The important surprise is that this is a numerical conversion, not a print proof. Actual CMYK appearance depends on the color profile, inks, press, and paper, while a browser can display only an RGB approximation.

Worked example

A concrete input and expected output from the current implementation.

Input

CMYK: 0%, 100%, 100%, 0%

Expected output

RGB: 255, 0, 0; Hex: #FF0000

With no cyan or black, the red channel remains at 255. Full magenta and yellow reduce the green and blue channels to 0, producing pure RGB red.

How the result is produced

CMYK to RGB

CMYK channels are percentages: cyan, magenta, yellow, and key (black). For CMYK to RGB, convert each percentage to a fraction, then calculate R = 255 * (1 - C) * (1 - K), G = 255 * (1 - M) * (1 - K), and B = 255 * (1 - Y) * (1 - K). The 8-bit results are rounded.

RGB, Hex, and CMYK

Hex does not define a separate color model here; it writes the red, green, and blue bytes as two hexadecimal digits each. In the reverse direction, RGB is normalized, K is derived from the largest channel, and C, M, and Y are calculated relative to the remaining range. Pure black is represented with K at 100% and C, M, and Y at 0%.

Good uses

Convert a printer-supplied CMYK brand color into an RGB and Hex starting point for a website.
Estimate CMYK percentages for a color supplied only as an RGB value or six-digit Hex code.
Compare screen swatches while reconciling color values used in print artwork and digital design files.

Limits and checks

The result is profile-independent arithmetic. It does not account for a specific ICC profile, printing process, ink set, or paper stock.
A displayed CMYK swatch is an RGB approximation because the browser and monitor cannot directly reproduce reflected ink colors.
Rounded 8-bit RGB values and rounded CMYK percentages can make a conversion followed by a reverse conversion differ slightly from the original.

Common questions

Will the converted Hex color exactly match the printed CMYK color?

No. Hex describes an RGB screen color, while printed CMYK depends on a particular output condition. The converted value is useful as a numerical approximation and coordination aid, but reliable matching requires color-managed applications, suitable ICC profiles, a calibrated display, and usually a physical proof from the intended printing process.

Why can different CMYK values convert to the same RGB color?

CMYK has four channels while RGB has three, so the relationship is not one-to-one. Black ink can replace combinations of cyan, magenta, and yellow without preserving a unique original recipe. Rounding can collapse additional nearby values. Converting back therefore produces a valid calculated CMYK representation, not necessarily the CMYK numbers initially entered.

References and verification

The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.