RGB to CMYK Converter
Turn screen RGB values into a print-ready CMYK starting point. The maths runs instantly in your browser — but because ink and light don't share a gamut, treat the result as a draft to be proofed.
C%
M%
Y%
K%
What is an RGB to CMYK converter?
An RGB to CMYK converter takes a colour defined by red, green and blue light — the way your monitor builds it — and expresses it as the four printing inks: cyan, magenta, yellow and a key black. It's the first step in moving artwork off the screen and onto paper.
The conversion this tool performs is the standard naive formula: black is pulled from the brightest channel, then each ink is derived from what's left. It's fast and predictable, which makes it perfect for getting a feel for a colour — but it is an approximation. Real print uses an ICC profile tuned to a specific press, paper and ink set, and that can shift the numbers noticeably.
Everything runs locally in your browser. Paste brand colours or unreleased design swatches freely — nothing is uploaded.
How to convert RGB to CMYK
- 1
Enter your RGB values
Type the red, green and blue channels, each from 0 to 255 — for example 0, 112, 220.
- 2
Read the CMYK output
The four ink percentages update instantly as a print-ready starting point.
- 3
Copy the values
Grab the CMYK string and drop it into Illustrator, InDesign, or your printer's spec sheet.
- 4
Proof before you commit
For anything brand-critical, request a physical proof — the screen can't promise the printed result.
Why designers reach for it
Fast print estimates
Get a credible CMYK figure in a second when you're spec'ing a layout or briefing a printer.
Understand the shift
Seeing the ink breakdown helps you predict which vivid screen colours will calm down on paper.
No software needed
Skip opening a heavy design app just to read one colour's CMYK equivalent.
Private by default
Confidential brand palettes are converted on your device and never leave it.
Example conversion
A typical brand blue, converted with the standard formula.
rgb(0, 112, 220)cmyk(100%, 49%, 0%, 14%)A starting point only — the exact ink mix depends on your paper and press profile.
Why the result is an approximation, not a final spec
RGB is an additive system: start from black and add light. CMYK is subtractive: start from white paper and subtract light with ink. Because light can be far more intense than reflected ink, the RGB gamut is larger — the brightest greens, blues and oranges on your screen simply have no exact ink recipe. The converter returns the closest the formula can manage, which is why a glowing on-screen blue often lands as a slightly muted print blue.
The honest takeaway: use these numbers to set up and visualise, then let your print provider's colour-managed workflow produce the authoritative values. The right ICC profile for the chosen stock will almost always differ a little from the generic formula here.
Where the difference bites hardest
- Neon and fluorescent colours, which CMYK cannot reach without special spot inks.
- Saturated cyans and greens that look electric on screen but dull on coated stock.
- Deep blacks — formula black isn't the same as a rich black built with supporting inks.
- Pastels, where small ink percentages behave very differently across paper types.
Frequently asked questions
No, and no online tool can make it exact. RGB describes light and CMYK describes ink, with a smaller gamut. The numbers here are a faithful mathematical approximation; the authoritative values come from a colour-managed workflow with the right ICC profile for your paper and press.
Because ink reflects less light than a screen emits. Bright, saturated RGB colours — especially greens, cyans and oranges — fall outside what CMYK can reproduce, so the formula maps them to the nearest achievable ink mix, which reads as more muted.
Design in RGB for screen and digital work, and convert to CMYK only when preparing files for print. Working in CMYK from the start limits your colour range unnecessarily for anything that will also live online.
You can round-trip the numbers with our CMYK to RGB converter, but expect small differences. Each crossing of the ink/light boundary loses a little precision, so a perfect reversal isn't guaranteed.
The naive formula splits black across cyan, magenta and yellow. For deep, dense blacks in print — like body text or a full-bleed background — many printers prefer a rich black recipe such as C:60 M:40 Y:40 K:100. After converting, manually adjust the K channel upward and reduce the other inks to get a richer, more even black.
Design apps convert through an ICC profile (often US Web Coated or a custom press profile), while this tool uses the generic formula. Different profiles mean different ink percentages — both are valid; one is tuned to a specific output.
Need another tool?
Browse the full toolbox or dig into the blog for the engineering behind it.