RGB to CMYK
Convert RGB screen colors to CMYK print values.
Type a RGB value or pick a color – the result updates instantly.
Preview
RGB to CMYK Converter
Have an RGB color from a website, screenshot, or design file and need it for print? Enter the channel values – for example 210, 105, 30 – and get cmyk(0%, 50%, 86%, 18%). The tool accepts rgb() notation, comma- or space-separated numbers, and percentages.
Additive light vs. subtractive ink
RGB starts from black and adds red, green, and blue light until it reaches white. CMYK starts from white paper and adds inks that absorb light. Cyan absorbs red, magenta absorbs green, and yellow absorbs blue, so each ink is roughly the opposite of one RGB channel. Black (K) is added because mixing the three colored inks produces a muddy brown rather than a clean black, and it saves ink.
Worked example: Chocolate
rgb(210, 105, 30) scales to R = 0.824, G = 0.412, B = 0.118.
- K = 1 − 0.824 = 17.6%
- C = (1 − 0.824 − 0.176) / 0.824 = 0%
- M = (210 − 105) / 210 = 50%
- Y = (210 − 30) / 210 = 85.7%
Rounded, the result is cmyk(0%, 50%, 86%, 18%).
| RGB | CMYK |
|---|---|
| 0, 0, 255 | 100%, 100%, 0%, 0% |
| 255, 255, 0 | 0%, 0%, 100%, 0% |
| 210, 105, 30 | 0%, 50%, 86%, 18% |
Before sending a file to print
- Pure RGB blue converts to 100% cyan plus 100% magenta, which prints as a violet-leaning blue – check it on a proof.
- Keep an eye on total ink coverage. Many presses limit C + M + Y + K to around 300%.
- Keep your master artwork in RGB and convert per job, since different papers and presses need different profiles.
For HEX input, use the HEX to CMYK converter. To preview how a CMYK specification looks on screen, try CMYK to RGB.
Frequently Asked Questions
Why do screen colors look different when printed?
Screens emit light and mix red, green, and blue additively, while ink absorbs light and mixes subtractively. The range of colors ink can reproduce is smaller, so bright, saturated RGB colors often print duller.
What formula does this converter use?
It uses the standard formula: K = 1 − max(R, G, B) with channels scaled to 0–1, then C = (1 − R − K) / (1 − K), M = (1 − G − K) / (1 − K), and Y = (1 − B − K) / (1 − K).
Is this the same as converting in Photoshop?
Not exactly. Photoshop converts through an ICC profile such as U.S. Web Coated (SWOP) or Coated FOGRA39, which models a specific press and limits total ink. This tool gives the device-independent values, which are a good starting point for specifications and brand guides.