About
A small, focused colour tool for people who work between screens and print — designers, prepress operators, and developers building palettes.
HexToCMYK converts HEX colours to CMYK ink percentages and back again, with RGB, HSL, a live swatch and a Total Ink Coverage check alongside. The bulk converter handles whole palettes at once and exports CSV, CSS variables, SCSS, JSON or a bare CMYK list.
Colour conversion between screen and print is a daily task with surprisingly few good tools. Spreadsheet formulas work for one colour at a time; many online converters upload your palette to a server, bury the result behind an account, or skip total ink coverage entirely — the one number prepress teams actually check before a job goes on press.
HexToCMYK does the whole job in the browser, instantly, with no account and no upload. That last part is deliberate: brand palettes under NDA should never leave the machine they were opened on.
CMYK output here is the standard sRGB approximation — the same formula every mainstream web converter uses. It is a faithful preview and a shared language for talking to your printer, not a press-calibrated specification. Real print output depends on the ICC profile, paper stock and press; treat these numbers as a starting point and let your printer’s proof have the final word.
HexToCMYK is an independent project, not affiliated with any printer, colour management vendor or design platform. It carries no advertising and sells nothing. If it saves you a round-trip to your prepress team, that is the whole business model.
Bugs, feature requests, or questions about the maths: hello@hextocmyk.com.