RGB to CMYK Converter
Turn the RGB values your screen shows into the four ink percentages a printer works with. Enter red, green and blue and read off cyan, magenta, yellow and key straight away.
Example conversion
rgb(220, 20, 60)
converts to
cmyk(0%, 91%, 73%, 14%)
About RGB to CMYK conversion
RGB and CMYK are not two spellings of the same thing - they are two physically different ways of making color. RGB is additive: a screen starts black and adds red, green and blue light until you see the color you want. CMYK is subtractive: paper starts white and each layer of cyan, magenta, yellow and black ink removes part of the light bouncing back at you. Converting between them means translating "how much light to emit" into "how much ink to lay down", which is why the numbers look nothing alike: RGB counts 0-255 per channel, CMYK counts 0-100% per ink.
The practical consequence is that some RGB colors simply cannot be printed. The vivid greens, electric blues and neon oranges a backlit screen produces sit outside the range - the gamut - that four process inks can reach. The conversion still gives you a value, but it is the closest printable relative of your color, not a perfect match. Knowing that in advance is exactly why you convert before sending artwork to print rather than after.
When should you use RGB to CMYK?
- Preparing artwork for print - flyers, posters, packaging, business cards and anything else that ends up on paper is produced in CMYK, not RGB.
- Filling in a print order form - print shops and merchandise suppliers usually ask for ink percentages rather than a hex code.
- Extending a digital brand into print - when a logo designed on screen needs a documented print equivalent.
- Sanity-checking a color before a print run - if the conversion returns something like 95% cyan and 57% magenta, you know you are asking for a heavy, saturated ink mix.
How the conversion works
Each RGB channel is first scaled from 0-255 down to 0-1. The black
channel comes from whichever channel is brightest: K = 1 - max(R, G,
B). That black ink carries the darkness, and the three colored inks
then only have to cover what is left, which is why the formula divides by
1 - K:
C = (1 - R - K) / (1 - K)M = (1 - G - K) / (1 - K)Y = (1 - B - K) / (1 - K)
Pure black is the one special case - there is no colored ink at all, so it converts to 0/0/0/100. This is the standard mathematical conversion, the same one design tools use for a quick answer. It is not color managed: it knows nothing about your specific press, paper or ink set. For a critical print run, get the ICC profile from your printer and soft-proof in your design software.
RGB vs CMYK
- Medium - RGB is for anything that emits light: screens, phones, projectors. CMYK is for anything printed with ink.
- Direction - RGB adds light to black; CMYK subtracts light from white.
- Channels - three channels of 0-255 versus four ink percentages of 0-100%.
- Range - RGB covers noticeably more saturated colors than four-color process printing can reproduce.
- White and black - on screen, white is all three channels at full and black is all off. In print it is reversed: white is no ink at all (the paper), and black is 100% K.
Named CSS colors in RGB and CMYK
The sixteen basic CSS color keywords plus eight more that come up constantly, each shown in both models side by side. Pick any row to drop that color into the converter and read it in the other eight models too.
Frequently asked questions
Why do my colors look duller after converting to CMYK?
Because ink cannot be as bright as light. A screen emits its own light and reaches saturations that reflected ink on paper physically cannot. When your RGB color falls outside the CMYK gamut, the conversion returns the nearest printable color, which usually reads as slightly darker or less vivid. Bright greens, cyans and oranges lose the most.
Should I convert images to CMYK myself before printing?
Usually not. Most modern print workflows prefer that you supply high-quality RGB images and let their color-managed RIP handle the conversion with the correct profile for their press and paper. Convert flat brand colors and vector artwork yourself; ask your printer what they want for photographs.
What is rich black and why is 0/0/0/100 sometimes not enough?
100% black ink alone can look washed out over large areas. Printers often use a "rich black" that adds some cyan, magenta and yellow underneath - something like 60/40/40/100 - for a deeper result. This converter gives the mathematically correct 0/0/0/100 for pure black; ask your printer for their preferred rich black recipe if you are filling a large area.
Does this converter use an ICC profile?
No. It applies the standard mathematical formula, which is ideal for quick conversions, web work and getting into the right ballpark. It does not simulate a specific press, paper stock or ink set. For color-critical work, use your printer's ICC profile in a design application that supports soft-proofing.
Can I convert CMYK back to RGB?
Yes - use the CMYK to RGB converter. Be aware that a round trip is not always lossless: if the original RGB color was outside the CMYK gamut, converting back returns the printable version, not your original color.