CMYK to RGB converter
Set cyan, magenta, yellow and key, and read the matching RGB value instantly. HueKit also shows hex, HSL and HSV so you have every format at once.
How do you convert CMYK to RGB?
Divide each CMYK percentage by 100 to get a fraction, then combine the key with each colored ink and scale up to the 0 to 255 range RGB uses:
- R = 255 x (1 - C) x (1 - K)
- G = 255 x (1 - M) x (1 - K)
- B = 255 x (1 - Y) x (1 - K)
Every step is a plain multiplication, so the answer updates the instant you drag a slider, and the only rounding is the final whole number per channel. Here is the same arithmetic on five inputs worth recognizing.
| CMYK | Working | RGB | Hex |
|---|---|---|---|
| 0, 0, 0, 0 | 255 x 1 x 1 on every channel | 255, 255, 255 | #FFFFFF |
| 100, 0, 0, 0 | R 255 x 0 x 1, G and B 255 x 1 x 1 | 0, 255, 255 | #00FFFF |
| 0, 100, 100, 0 | R 255 x 1 x 1, G and B 255 x 0 x 1 | 255, 0, 0 | #FF0000 |
| 20, 40, 0, 10 | 255 x 0.8 x 0.9, 255 x 0.6 x 0.9, 255 x 1 x 0.9 | 184, 138, 230 | #B88AE6 |
| 0, 0, 0, 100 | 255 x 1 x 0 on every channel | 0, 0, 0 | #000000 |
Why does every CMYK to RGB converter give a different answer?
Because CMYK numbers do not describe a color. They describe how much of four inks to lay down, and the color that results depends on which inks, which paper and which press. Coated stock, uncoated stock, newsprint and a desktop inkjet all turn the same four percentages into visibly different colors. The formula above quietly assumes an idealized, device-independent CMYK that no printing process actually is.
The real answer lives in an ICC profile: a file that characterizes one specific combination of ink, substrate and process, published and maintained under the International Color Consortium specification. Common examples are the coated offset profiles built on the FOGRA characterization data behind ISO 12647-2, and the SWOP based profiles used for North American web offset. Convert the same CMYK values through two of those and you get two different RGB answers, both correct for their own process.
There is a second source of divergence on top of that. A color-managed conversion also applies a rendering intent, and the ICC specification defines four: perceptual, media-relative colorimetric, saturation and ICC-absolute colorimetric. They handle out of gamut colors differently, so the choice of intent changes the numbers again. Add profile plus intent together and the honest conclusion is that there is no single right RGB value for a CMYK input, which is exactly why converters disagree.
Which RGB does the result mean?
sRGB, the space standardized as IEC 61966-2-1 and the default assumption for anything on the web. That matters more than it used to. If you paste 184, 138, 230 into a document set up for Display P3 or Adobe RGB without tagging it as sRGB, the same three numbers describe a different, more saturated color. When you hand a value to a developer, say sRGB; when you hand it to a printer, hand over the CMYK build instead.
Why does the RGB look brighter than the printed color?
Look at the second row of the table. C 100, M 0, Y 0, K 0 becomes RGB 0, 255, 255, the most saturated cyan a screen can emit. Cyan process ink on paper is nowhere near that vivid. The same effect shows up at the other end: CMYK 0, 0, 0, 100 converts to pure black #000000, while 100 percent black ink alone prints as a dark charcoal, which is why designers build a rich black by adding cyan, magenta and yellow underneath the key.
Underneath that is the gamut problem. The two models cover overlapping but different ranges of color, and neither contains the other. Vivid screen blues, greens and oranges regularly fall outside what process inks can hit, while a handful of saturated ink colors sit outside sRGB. Any conversion between them involves compressing or clipping colors that have nowhere to go, which is precisely the job a rendering intent is doing.
When is this converter the right tool?
It is the right tool when you need a fast, repeatable, on-screen equivalent: turning a CMYK brand build into a hex value for a website, previewing a print palette in a mockup, filling in a color field in a design tool, or checking roughly where a value sits. The formula is deterministic, so you and a colleague running the same input will get the same output, which is often more useful than being marginally more accurate but unreproducible.
It is the wrong tool when the color has to match a physical proof. For that, work inside a color-managed application with the exact ICC profile your printer specifies, soft proof on a calibrated display, and trust a printed proof over any screen. If a brand has an official Pantone or spot color, use the brand's published RGB and CMYK builds rather than converting one into the other.
When do you need this conversion?
Designers usually work in CMYK for print and RGB or hex for the web, so this jump comes up whenever a brand color has to live in both places: a logo sheet that only lists CMYK, a print ad being adapted into a banner, or a palette handed over from an agency. For the reverse direction, use the RGB to CMYK converter; to go straight to a web-ready value, the CMYK to hex converter skips a step, and the hex to RGB converter covers the most common web jump. If you are pulling colors out of a printed piece you photographed, the palette from image tool is a better starting point than guessing at ink percentages.
Frequently asked questions
How do I convert CMYK to RGB?
Divide each CMYK percentage by 100, then apply R = 255 x (1 - C) x (1 - K), G = 255 x (1 - M) x (1 - K) and B = 255 x (1 - Y) x (1 - K), rounding each channel to a whole number. HueKit runs that math live as you move the sliders and shows hex, HSL and HSV alongside it.
What is the CMYK to RGB formula?
R = 255 x (1 - C) x (1 - K), G = 255 x (1 - M) x (1 - K), B = 255 x (1 - Y) x (1 - K), with C, M, Y and K expressed as fractions from 0 to 1. For example CMYK 20, 40, 0, 10 gives R = 255 x 0.8 x 0.9 = 184, G = 255 x 0.6 x 0.9 = 138 and B = 255 x 1 x 0.9 = 230, which is #B88AE6.
Is there one correct RGB value for a CMYK color?
No, and this is the part most converters do not say out loud. CMYK numbers only describe how much ink to lay down; the color that produces depends on the ink set, the paper and the press, which is what an ICC profile records. Without a profile there is no single right answer, only a reasonable approximation, which is why two converters can disagree on the same input.
Which RGB color space does the result use?
sRGB, standardized as IEC 61966-2-1 and the default assumption for the web. If you paste the value into a wide gamut workflow such as Display P3 or Adobe RGB and it is not tagged as sRGB, the same numbers will render as a different color.
Why does CMYK to RGB not always match perfectly?
CMYK is subtractive, ink absorbing light from white paper, while RGB is additive light emitted by a screen. Their gamuts overlap but neither contains the other, so some printable colors cannot be shown on screen and many screen colors cannot be printed. The converter gives the closest standard RGB value, not a promise about how the ink will look.
Why does 100 percent cyan look so much duller in print?
Because the formula maps C 100, M 0, Y 0, K 0 to RGB 0, 255, 255, the most saturated cyan a screen can emit. Real cyan process ink on paper is noticeably darker and less saturated than that, so the on-screen preview flatters it. This is a limit of any profile-free conversion, not a bug in the arithmetic.
What does the K in CMYK stand for?
K is the key plate, which carries black. Printers add a dedicated black ink instead of layering cyan, magenta and yellow, because that gives cleaner text and deeper shadows while using less colored ink.
Sources
- International Color Consortium, for what an ICC profile is and the four rendering intents defined in the ICC specification.
- ISO 12647-2, the process control standard for offset lithographic printing that the common coated CMYK profiles characterize, published by the International Organization for Standardization.
- IEC 61966-2-1, the International Electrotechnical Commission standard that defines sRGB, the color space the RGB output here assumes.