What formula does the converter use?

K = 1 − max(R, G, B) with channels scaled to 0–1; then C = (1 − R − K) / (1 − K), and the same for M with G and Y with B. Pure black is 0 % C, M and Y with 100 % K.

Will my print match the screen?

Not exactly. Printed color depends on the press, inks, paper and the ICC color profile used. This formula ignores profiles, so treat the result as an approximation and ask your print shop for their profile for professional work.

Why do some bright screen colors look dull in print?

Screens can show some colors — very saturated greens, blues and oranges — that CMYK inks cannot reproduce. These out-of-gamut colors print as the nearest achievable color.

RGB to CMYK Converter

Enter an RGB color to get approximate CMYK percentages for print.

RGB values (0–255)

rgb(30, 144, 255)

CMYK: cmyk(88%, 44%, 0%, 0%)
Precise1 decimal: C 88.2% M 43.5% Y 0% K 0%
HEX: #1E90FF

Converting back? Use the CMYK to RGB converter.

Approximation: this uses the standard formula without an ICC color profile. Real print results depend on the printer, inks and paper — for professional print, convert with the profile your print shop specifies.

How to convert RGB to CMYK

Enter the red, green and blue values (0–255) of your screen color.
Read the CMYK percentages — rounded for everyday use, or with one decimal.
Copy the values into your print or layout software, then check a proof.

Why CMYK conversion is an approximation

RGB describes light from a screen; CMYK describes cyan, magenta, yellow and black ink on paper. The same CMYK numbers print differently on different presses, inks and papers, which is why professional workflows convert with an ICC color profile (such as the one your print shop uses). This converter uses the standard profile-free formula: a reliable starting point, but not a guaranteed match for professional print output.

The formula (R, G and B scaled to 0–1)

K = 1 − max(R, G, B)
C = (1 − R − K) / (1 − K)
M = (1 − G − K) / (1 − K)
Y = (1 − B − K) / (1 − K)

RGB to CMYK examples

Screen colors and their approximate CMYK values
HEX	RGB	CMYK
#000000	0, 0, 0	0%, 0%, 0%, 100%
#FFFFFF	255, 255, 255	0%, 0%, 0%, 0%
#FF0000	255, 0, 0	0%, 100%, 100%, 0%
#00FF00	0, 255, 0	100%, 0%, 100%, 0%
#0000FF	0, 0, 255	100%, 100%, 0%, 0%
#00FFFF	0, 255, 255	100%, 0%, 0%, 0%
#FF00FF	255, 0, 255	0%, 100%, 0%, 0%
#FFFF00	255, 255, 0	0%, 0%, 100%, 0%
#808080	128, 128, 128	0%, 0%, 0%, 50%
#1E90FF	30, 144, 255	88%, 44%, 0%, 0%

Related color tools

Convert back with CMYK to RGB, get RGB from a HEX code with HEX to RGB, or find a color with the color picker, which also shows CMYK.

Frequently asked questions

What formula does the converter use?: K = 1 − max(R, G, B) with channels scaled to 0–1; then C = (1 − R − K) / (1 − K), and the same for M with G and Y with B. Pure black is 0 % C, M and Y with 100 % K.
Will my print match the screen?: Not exactly. Printed color depends on the press, inks, paper and the ICC color profile used. This formula ignores profiles, so treat the result as an approximation and ask your print shop for their profile for professional work.
Why do some bright screen colors look dull in print?: Screens can show some colors — very saturated greens, blues and oranges — that CMYK inks cannot reproduce. These out-of-gamut colors print as the nearest achievable color.