Hex to CMYK converter
Paste a hex colour code and get the matching CMYK ink percentages — cyan, magenta, yellow and key (black) — for print and design work, with a live swatch and a one-click copy. Screens mix light (RGB), but printers mix ink (CMYK), so a hex value from your design has to be translated before it goes to press.
How it works
The tool first parses the hex into red, green and blue (0–255), expanding 3-digit shorthand if needed. It normalises each channel to a 0–1 range, then applies the standard RGB-to-CMYK formula:
- K (black) = 1 − max(R, G, B)
- C = (1 − R − K) / (1 − K)
- M = (1 − G − K) / (1 − K)
- Y = (1 − B − K) / (1 − K)
Each result is multiplied by 100 and rounded to a whole percent. Pure black is a special case (K = 100, the rest 0).
Worked example
For #3b82f6 (a vivid blue), the RGB is 59, 130, 246. Normalised to 0–1: R = 0.231, G = 0.510, B = 0.965.
- K = 1 − max(0.231, 0.510, 0.965) = 1 − 0.965 = 0.035 → 4%
- C = (1 − 0.231 − 0.035) / (1 − 0.035) = 0.734 / 0.965 = 76%
- M = (1 − 0.510 − 0.035) / 0.965 = 0.455 / 0.965 = 47%
- Y = (1 − 0.965 − 0.035) / 0.965 = 0 / 0.965 = 0%
Result: cmyk(76%, 47%, 0%, 4%).
Common conversions at a glance
| Hex | R, G, B | Approx. 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% |
#3b82f6 | 59, 130, 246 | 76%, 47%, 0%, 4% |
#f97316 | 249, 115, 22 | 0%, 54%, 91%, 2% |
Why CMYK is different from RGB for printing
RGB is additive — screens start from black and add red, green, and blue light to reach white. CMYK is subtractive — paper starts from white and inks absorb (subtract) wavelengths to create colour. A mix of cyan, magenta, and yellow theoretically produces black, but in practice the result is a muddy dark brown, which is why key (black) ink is used separately for clean black text, sharp details, and cost savings (black ink is cheaper per unit than colour ink).
The K value in the formula is extracted first (as the “how dark” component), then the remaining colour is expressed in CMY relative to that remaining lightness. This is why a dark colour like navy blue produces a high K along with some C and M, rather than pure CMY.
Print accuracy and colour management
The mathematical conversion in this tool gives a good starting point for screen-to-print translation, but professional print workflows use ICC colour profiles (such as FOGRA39 for European offset printing or SWOP for US publishing) to account for the specific ink and paper combination. The same CMYK values print differently on coated versus uncoated paper, and differently again across inkjet, offset, and digital presses.
For branding-critical print work (logos, packaging, marketing materials):
- Convert hex to CMYK here to get a working estimate.
- Request a printed press proof or colour match from your printer.
- Ask your printer for their recommended ICC profile and confirm the values in a professional design tool like Adobe Illustrator or InDesign.
For everyday print needs — stationery, presentations, simple marketing pieces — the mathematical CMYK from this converter is a practical and reliable guide.
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