Convert RGB colors to CMYK and back — instantly
Conversion Direction
Convert RGB to CMYK and back with this free online tool. Whether you're preparing artwork for print or translating screen colors to press-ready values, our RGB to CMYK converter handles both directions instantly. Enter values by hand, drag sliders, or use the built-in color picker — results update live with full CMYK percentages, RGB triplets, and HEX output ready to copy.
RGB is an additive color model used by screens (mixing light), while CMYK is subtractive and used in print (mixing ink). The two models have different color gamuts, so some vivid RGB colors — especially bright blues, greens, and neons — cannot be reproduced exactly with CMYK inks.
Each RGB channel (0–255) is first normalized to 0–1. The black key K equals 1 minus the maximum channel value. The C, M, and Y values are then calculated as (1 − channel − K) ÷ (1 − K), expressed as percentages. This produces the standard CMYK formula used by most design software.
The mathematical conversion is deterministic, but small rounding differences of ±1 can appear due to floating-point precision. This is normal and matches the behavior of tools like Photoshop and Illustrator. For professional print work, always do a soft-proof in your design application using your printer's ICC profile.
For single-color black text, use C:0 M:0 Y:0 K:100 — this is called 'rich black lite' and produces crisp, clean text without registration issues. The 'rich black' formula (C:60 M:40 Y:40 K:100) is better suited to large solid areas and backgrounds.