Convert CMYK values to a hex code

First work out three channels of light from the four inks, then write each channel as two hexadecimal characters. Percentages go into the formula as fractions, so 76% becomes 0.76.

The formula: R = 255 × (1 − C) × (1 − K). Green comes from magenta in the same way, and blue from yellow.

For cmyk(76%, 47%, 0%, 4%) the red channel is 255 × 0.24 × 0.96, which is 59, green is 130 and blue is 245. Now divide each number by 16: 59 is 3 sixteens with 11 left over, and 11 is the letter B, so red becomes 3B. In the same way 130 becomes 82 and 245 becomes F5. The result is #3B82F5.

The CMYK to RGB converter stops halfway, at the three numbers. To turn a screen code into inks, use the HEX to CMYK converter.

The four CMYK numbers are a recipe for the press: how much of the paper to cover with cyan, magenta, yellow and black, the key plate[1]. That is why you find them in printer spec sheets and brand guides, since they describe ink rather than what appears on a screen.

The six hex characters are three numbers from 0 to 255 written in base 16, two characters each for red, green and blue light[2]. This is the code you paste into CSS, a website theme, Canva or Figma.

The result always has six characters, because ink has no transparency and there is nothing to put in a seventh and eighth character. We write the code in capitals, although a browser reads #3b82f5 the same way[2].

If your color is in another format, such as OKLCH, Lab or Android code, the color converter shows it in every format at once.

Use the one in the brand guide. The formula assumes perfect inks on perfectly white paper, so its result comes out lighter and more saturated than a real print. The hex code in a guide usually sits much closer to what you see on paper.

The HM Government brand palette shows this clearly. For Pantone 660 C the guidelines give 77% cyan and 46% magenta together with the code #3D7DCA, and they state that these breakdowns were taken from Adobe Photoshop[3]. The formula turns the same inks into #3B8AFF, a bright, glowing blue. We ran the inks through two press profiles with the Little CMS library[4]: GRACoL 2013 from the ICC registry[5] gives #427BBA, and PSO Coated v3 from the European Color Initiative[6] gives #3977B9, both close to the code in the guidelines.

When a guide lists only CMYK, the converter gives you a working code. Compare it with a printed flyer or business card, and darken the color in Figma or your stylesheet if it glows more on screen than on paper.