About

CMYK (Cyan, Magenta, Yellow, Key/Black) is a subtractive color model used in commercial printing. RGB (Red, Green, Blue) is an additive model for screens. Mapping between them is non-trivial because CMYK gamuts do not perfectly overlap RGB gamuts. This tool computes the standard uncalibrated conversion: R = 255 × (1 − C) × (1 − K). It assumes no ICC profile. For press-accurate results you need a calibrated profile from your print house. Without conversion, colors sent directly from screen to press will shift - typically losing saturation in blues and greens.

The converter also outputs Hex notation and HSL values. All values update in real time. Note: this conversion is device-independent and approximates. Pantone spot colors or colors outside sRGB gamut cannot be perfectly represented. Pro tip: always request a physical proof from your printer before committing to a full run.

Formulas

The standard device-independent CMYK to RGB conversion treats each channel as a percentage (0 - 100) and maps it to the 0 - 255 RGB range. The Key channel K acts as a global darkening factor applied multiplicatively.

R = 255 × (1 − C100) × (1 − K100)

G = 255 × (1 − M100) × (1 − K100)

B = 255 × (1 − Y100) × (1 − K100)

Where C = Cyan (0 - 100%), M = Magenta (0 - 100%), Y = Yellow (0 - 100%), K = Key/Black (0 - 100%). The result is rounded to the nearest integer clamped to [0, 255]. Hex is derived by converting each channel to a two-digit base-16 string.

Reference Data

Color Name	C	M	Y	K	R	G	B	Hex
Black	0	0	0	100	0	0	0	#000000
White	0	0	0	0	255	255	255	#FFFFFF
Pure Red	0	100	100	0	255	0	0	#FF0000
Pure Green	100	0	100	0	0	255	0	#00FF00
Pure Blue	100	100	0	0	0	0	255	#0000FF
Pure Cyan	100	0	0	0	0	255	255	#00FFFF
Pure Magenta	0	100	0	0	255	0	255	#FF00FF
Pure Yellow	0	0	100	0	255	255	0	#FFFF00
Orange	0	35	100	0	255	166	0	#FFA600
Dark Green	100	0	100	50	0	128	0	#008000
Navy	100	100	0	50	0	0	128	#000080
Teal	100	0	0	50	0	128	128	#008080
Maroon	0	100	100	50	128	0	0	#800000
Olive	0	0	100	50	128	128	0	#808000
Silver	0	0	0	25	191	191	191	#BFBFBF
Gray	0	0	0	50	128	128	128	#808080
Coral	0	50	69	0	255	128	79	#FF804F
Sky Blue	43	8	0	0	145	235	255	#91EBFF
Gold	0	17	100	0	255	212	0	#FFD400
Lavender	10	10	0	0	230	230	255	#E6E6FF

Frequently Asked Questions

This converter uses the standard uncalibrated formula without an ICC color profile. Printers use specific ink sets whose gamut differs from sRGB. The formula R = 255 × (1 − C/100) × (1 − K/100) is device-independent and does not account for dot gain, paper absorption, or ink density. For press-accurate matching, request an ICC profile from your print house and use a color management system like Adobe Color.

When K = 100, the multiplier (1 − K/100) becomes 0, forcing R, G, and B all to 0 regardless of C, M, or Y values. This produces pure black (#000000). In practice, print shops rarely use K = 100 alone - they use "rich black" with added CMY channels (e.g., C=40, M=40, Y=40, K=100) for denser coverage, but the RGB output remains #000000 for any combination where K = 100.

No. The CMYK gamut is smaller than sRGB. Highly saturated blues (like #0000FF) and vibrant greens cannot be perfectly reproduced in CMYK printing. Conversely, some CMYK mixtures produce colors outside sRGB. This tool converts the mathematical value, but the physical print may clip to the nearest reproducible tone. Fluorescent and metallic inks extend CMYK gamut but are not modeled here.

ICC profiles encode device-specific lookup tables (LUTs) that map CMYK ink densities to measured CIE Lab values, then to RGB. This accounts for paper type, ink lot, humidity, and dot gain. The formula used here is a linear algebraic approximation that ignores all physical variables. For web mockups and rough previews, this formula is standard. For prepress proofing, always use ICC-based software.

Yes. Professional design software (Adobe InDesign, Illustrator) allows fractional CMYK percentages. This tool accepts decimals from 0 to 100 and rounds the final RGB output to integers since RGB channels are 8-bit (0-255). A difference of 0.5% in CMYK typically shifts RGB by 1 unit at most, which is imperceptible on screen.

CMYK is a print color model with no concept of transparency - paper is the background. RGB likewise has no native alpha. RGBA adds a fourth channel for screen compositing, but it has no CMYK equivalent. If you need transparency, apply it separately in your design tool after converting the base color.