Convert RGB to CMYK instantly — enter a color, upload an image, or pick from the color wheel to get accurate CMYK percentages for print.
RGB Input
Or Sample From an Image
Click anywhere on the image to sample that pixel’s color.
CMYK Output
CMYK values are calculated using the standard uncalibrated RGB-to-CMYK formula. Actual print output varies by printer, paper, and ICC color profile, so treat these numbers as a starting point and confirm against a proof before final production.
How the RGB to CMYK Conversion Formula Works
RGB to CMYK conversion works by first calculating black (K) from the darkest of the three RGB channels, then deriving cyan, magenta, and yellow relative to that black value.
The formula, using RGB values normalized to a 0–1 scale (R’ = R/255, G’ = G/255, B’ = B/255):
K = 1 − max(R', G', B')
C = (1 − R' − K) / (1 − K)
M = (1 − G' − K) / (1 − K)
Y = (1 − B' − K) / (1 − K)Each result (C, M, Y, K) is a decimal between 0 and 1, which this tool multiplies by 100 to display as a percentage — the standard format used in print and design software like Adobe Illustrator and Photoshop.
Worked example: navy blue RGB(15, 13, 114) normalizes to R’=0.059, G’=0.051, B’=0.447. K = 1 − 0.447 = 0.553 (55%). From there, C = 87%, M = 89%, Y = 0%, K = 55%.
Why RGB to CMYK Conversion Isn’t Always Exact
RGB and CMYK are built for different purposes — RGB describes light emitted from a screen, while CMYK describes ink absorbed by paper — so no formula produces a perfect match between the two. This tool uses the standard uncalibrated conversion formula, which is accurate for estimating print values but doesn’t account for a specific printer’s ink, paper stock, or ICC color profile. For color-critical print jobs (brand logos, packaging, large print runs), always confirm the CMYK values against a physical proof or your print vendor’s calibrated profile before final production.
When to Use RGB to CMYK Conversion
- Preparing client branding assets for print — business cards, brochures, and signage need CMYK values, while the same logo lives in RGB on the client’s website
- Handing off design files to a print vendor — vendors typically require CMYK color specs, not the RGB/hex values used in web design tools
- Sampling a brand color from an existing image — pull the exact RGB value from a logo or photo, then convert it to CMYK for print-ready documentation
FAQ
How do I convert RGB to CMYK?
Enter your RGB values (or a hex code) into the converter above, and the CMYK percentages update instantly. The conversion works by calculating black (K) from the darkest RGB channel, then deriving cyan, magenta, and yellow proportionally.
What is the RGB to CMYK conversion formula?
K = 1 − max(R, G, B), then C, M, and Y are each calculated as (1 − channel − K) / (1 − K), using RGB values normalized to a 0–1 range. The full breakdown with a worked example is above.
Is RGB to CMYK conversion always accurate?
Not exactly — RGB and CMYK represent color differently (light vs. ink), so this tool’s output is a reliable estimate using the standard conversion formula, not a substitute for your printer’s calibrated ICC profile. Always check a physical proof for color-critical print jobs.
Why does my printed color look different from what I see on screen?
Screens display color as emitted light (RGB), while printers reproduce color using layered ink (CMYK), and that fundamental difference — plus paper stock, ink type, and printer calibration — means colors rarely match exactly between screen and print.
Can I convert an image’s color to CMYK, not just numbers I type in?
Yes — upload an image using the tool above, then click anywhere on it to sample that pixel’s RGB color, which automatically converts to CMYK.