CMYK to RAL Colour Converter

Convert CMYK values to the nearest RAL Classic colour.

C (%)

M (%)

Y (%)

K (%)

—

How the nearest RAL match is calculated

Your colour is compared against all 217 RAL Classic colours and the closest one is returned, using a weighted RGB distance (the "redmean" approximation) which weights the channels closer to how the eye perceives them than a plain Euclidean distance would. Everything runs in your browser.

Important: RAL colours are not RGB values

RAL Classic colours are defined by physical paint samples, not by screen values. The hex values used here are the widely used screen approximations from Wikipedia's List of RAL colours, and the same RAL code can look noticeably different when printed on different substrates. Use this converter for on-screen reference only — for paint mixing, printing or production work, always confirm against a physical RAL fan deck.

See the full RAL Classic chart (all 217 colours) →

How it works

CMYK is first converted to RGB with the simple subtractive formula R = 255 x (1 - C) x (1 - K), then matched to the nearest RAL Classic colour.

Examples

Input	Output
cmyk(0,10,40,10)	RAL 1014 Ivory
cmyk(0,30,100,0)	RAL 1023 Traffic yellow
cmyk(80,30,0,10)	RAL 5012 Light blue

Frequently Asked Questions

Is the CMYK conversion accurate?

No - this uses a simple subtractive formula without an ICC profile, so it approximates what a printed CMYK value may look like on screen. Real printing depends on ink, paper and press profile.

Why is there no exact CMYK to RAL conversion?

Because both are device-dependent: CMYK depends on the printing process, and RAL is defined by physical paint samples.

What if my CMYK values are 0-1 instead of 0-100?

Enter them as percentages, e.g. 0-100. Values above 100 are treated as 100%.