CMYK ↔ RGB Converter
Convert between RGB (sRGB display) and CMYK (process print).
Overview
The CMYK ↔ RGB Converter translates between additive sRGB values used by screens and the subtractive cyan-magenta-yellow-key channels used by process printing. Paste a hex code or enter four CMYK percentages and the tool reports the equivalent representation alongside a live swatch preview.
It targets brand designers preparing print-ready assets, illustrators bridging web mock-ups and offset proofs, and developers exporting colour tokens for both digital and physical deliverables. While no algorithmic conversion can replace an ICC-managed press, the result is a solid starting point for spec sheets and approximate previews.
How it works
Pure RGB → CMYK uses the device-naive formula: K = 1 − max(R, G, B), then C = (1 − R − K) / (1 − K), M = (1 − G − K) / (1 − K), Y = (1 − B − K) / (1 − K). The inverse multiplies each chromatic channel by (1 − K) and complements the result. All inputs are normalised to 0–1 before the maths runs.
This is the standard "naive" conversion — it ignores press dot gain, ink limits and substrate colour, which is why professional workflows wrap it in an ICC profile. For screen-only mock-ups the naive form is sufficient and reversible.
Examples
#ff6600 → C 0% M 60% Y 100% K 0%
#1a73e8 → C 89% M 50% Y 0% K 9%
#000000 → C 0% M 0% Y 0% K 100%
#ffffff → C 0% M 0% Y 0% K 0%
FAQ
Why does my print look duller than the screen preview?
Screens emit light additively and can reach colours outside the CMYK gamut (especially vivid blues, greens and oranges). Those colours are mathematically reachable but the press cannot reproduce them, so the printed result desaturates.
What is the K channel for?
Mixing C, M and Y alone produces a muddy brown rather than true black, and uses three times the ink. Adding a dedicated black plate gives crisper text and reduces overall ink coverage.
Are these values press-accurate?
No. Use them as a starting point. For production work convert through an ICC profile that matches your press, paper and ink set — for example GRACoL 2013 for North American coated stock.
Can I round-trip RGB → CMYK → RGB without loss?
For colours inside the CMYK gamut, yes — the naive formula is reversible. Out-of-gamut RGB values clamp during the conversion and will not return to their exact original.