๐จ CMYK Color Converter
Convert between RGB (hex color codes) and CMYK (cyan/magenta/yellow/key-black print ink mix). Useful for translating a web color into an approximate print ink mix, and vice versa.
How to use
- Choose "RGB to CMYK" or "CMYK to RGB" mode.
- For RGB, enter a hex color code; for CMYK, enter C/M/Y/K percentage values.
- The converted result is shown automatically.
How the calculation works
This tool converts between RGB, used on screens, and CMYK, used in print, with the common simplified formulas. For RGB to CMYK, R, G and B are first scaled to 0โ1. K (black) is 1 minus the largest of them, and the other inks cover what black cannot: K = 1 โ max(R, G, B) C = (1 โ R โ K) รท (1 โ K) M = (1 โ G โ K) รท (1 โ K) Y = (1 โ B โ K) รท (1 โ K) CMYK to RGB uses the reverse, R = 255 ร (1 โ C) ร (1 โ K) and so on. Hex codes can be six digits (#e63946) or three-digit shorthand (#f00 means #ff0000). This is a purely mathematical mapping that ignores ink and paper characteristics. Matching printed colour requires colour management with the ICC profile your printer specifies (such as Japan Color or FOGRA).
Worked example
RGB โ CMYK #e63946 (R230 G57 B70) K = 1 โ 230/255 โ 0.098 โ 9.8% C = 0%, M โ 75.2%, Y โ 69.6% #ff0000 (red) โ C0% M100% Y100% K0% #000000 (black) โ C0% M0% Y0% K100% CMYK โ RGB C0% M75% Y69% K10% โ #e63947
Things to be aware of
- Some vivid colours that screens can show (bright greens and blues, for example) cannot be reproduced with CMYK inks, so prints can look duller than the screen.
- In this simple formula, greys and black use K only. Real print work sometimes uses "rich black", adding C, M and Y for a deeper black.
- For print-ready files, use the CMYK values produced by your design software's colour settings.
FAQ
What formula does this use?
A common simplified conversion (K = 1 - max(R,G,B), C = (1-R-K)/(1-K), etc.). Real print results vary with ink, printer, and paper, so treat this as an approximation.
Why might this look different from what a print shop produces?
This is a simple mathematical conversion. Real printing involves ICC color management and ink/paper characteristics, so accurate color reproduction requires your print shopโs color management process.
What is K (the key plate)?
The black ink component. Mixing only cyan, magenta, and yellow to produce black gives poor results and costs more ink, so print processes use a separate black (K) ink.