CMYK to RGB Converter

How to use the CMYK to RGB Converter

Type or paste CMYK values into the CMYK field, such as cmyk(61%, 28%, 0%, 29%).

Use percentages, plain numbers or 0–1 fractions for the four inks.

The RGB field shows rgb(r, g, b), calculated with the standard formula, as you type.

Copy the RGB value with the button next to the field into your image editor, code or design file.

CMYK to RGB with the standard formula

This CMYK to RGB converter applies the textbook formula that links ink percentages to screen channels. It is what you need when a print specification has to be recreated in software that only accepts red, green and blue, from image editors to game engines.

The formula

R = 255 × (1 − C) × (1 − K)
G = 255 × (1 − M) × (1 − K)
B = 255 × (1 − Y) × (1 − K)

C, M, Y and K are fractions from 0 to 1. Read it as light being filtered twice: once by the color ink and once by the black. Cyan ink absorbs red light, magenta absorbs green and yellow absorbs blue, which is why each ink appears only in its opposite channel.

Worked example

cmyk(61%, 28%, 0%, 29%)

R = 255 × 0.39 × 0.71 =  70.6 →  71
G = 255 × 0.72 × 0.71 = 130.4 → 130
B = 255 × 1.00 × 0.71 = 181.1 → 181

→ rgb(71, 130, 181)

That is within one step of steelblue, rgb(70, 130, 180). The gap comes from the CMYK percentages being rounded to whole numbers.

Accepted notations

cmyk(61%, 28%, 0%, 29%), 61 28 0 29 and 0.61, 0.28, 0, 0.29 all give rgb(71, 130, 181).
Values above 100% are clamped, so cmyk(150%, 0%, 0%, 0%) is treated as 100% cyan.
Four values are required; an entry with three numbers is reported as invalid.

The color management caveat

This formula is not ICC color-managed. Professional software such as InDesign or Photoshop converts CMYK through a profile describing a real printing condition, including paper whiteness, ink behavior and dot gain. The same CMYK numbers can therefore produce different RGB values there, and both can differ from what a particular press prints.

For web mockups, quick previews and documentation, the simple formula is consistent and easy to reproduce in code. For color-critical work, such as matching packaging, use the printer's profile and a physical proof.

Common mistakes

Adding K instead of multiplying. Black scales every channel; it is not subtracted separately from each.
Using 0–100 in the formula. Convert percentages to fractions first, or the result goes negative.
Expecting RGB to CMYK to return your original values. The reverse formula always puts the shared darkness into K, so cmyk(20%, 60%, 100%, 20%) comes back as a different recipe for the same color.

The reverse tool is RGB to CMYK. For a hex code go to CMYK to HEX, and for a CSS value with transparency use CMYK to RGBA.

Frequently asked questions

What is the formula to convert CMYK to RGB?

R = 255 × (1 − C) × (1 − K), G = 255 × (1 − M) × (1 − K) and B = 255 × (1 − Y) × (1 − K), with all ink values as fractions from 0 to 1. Round each result to a whole number.

Why does Photoshop give different RGB numbers for the same CMYK?

Photoshop converts through the CMYK and RGB profiles in its color settings, which model a real press and paper. This tool uses the simple unmanaged formula, so results can differ, especially for dark and saturated colors.

Does CMYK to RGB lose information?

Several CMYK recipes can map to the same RGB color, because black and the color inks can substitute for each other. The RGB result keeps the color but not the specific ink mix.

What RGB value is 100% black ink?

cmyk(0%, 0%, 0%, 100%) is rgb(0, 0, 0). Any value with K at 100% gives black, whatever the other inks are.