Convert CMYK values back to RGB for on-screen use. Enter the four ink percentages and get rgb() in both syntaxes plus hex, with a live swatch — and a clear note that a screen preview of ink is always an approximation of what paper will do.
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Subtractive in, additive out
This direction models what your eye does at the newsstand: inks subtract portions of white light, and what reflects is the color. The math mirrors that physics in idealized form — each RGB channel is the light surviving its opposing ink and the black layer.
Worked example: cmyk(0%, 55%, 100%, 9%)
A printed orange:
R = 255 × (1 − 0.00) × (1 − 0.09) ≈ 232 G = 255 × (1 − 0.55) × (1 − 0.09) ≈ 104 B = 255 × (1 − 1.00) × (1 − 0.09) = 0 cmyk(0%, 55%, 100%, 9%) ≈ #e86800
Full yellow ink zeroes the blue channel completely — the starkest demonstration of “ink removes light” the model offers. The 9% black shaves every channel proportionally.
What this direction is good for
Safe by nature: everything ink can print, screens can show, so no gamut trap waits in this direction. Use it to bring printed brand specs onto the web, to build screen mockups of packaging, or to decode a vendor’s recipe into something a browser can render for stakeholders.
And its limits
Idealized inks are not real inks: process cyan reflects stray red, yellows are impure, and paper is never a true white. Add dot gain and lighting metamerism and the honest claim is “this is the color the recipe aims at”, not “this is what the sheet will look like”. For that, there are proofs.
Reference values, computed live
Recipes become concrete when you can see what they cook. Seven ink specifications and the screen colors the standard reconstruction produces:
| Color | CMYK | RGB |
|---|---|---|
| tomato | cmyk(0%, 61.2%, 72.2%, 0%) | rgb(255, 99, 71) |
| mediumseagreen | cmyk(66.5%, 0%, 36.9%, 29.8%) | rgb(60, 179, 113) |
| mediumpurple | cmyk(32.9%, 48.9%, 0%, 14.1%) | rgb(147, 112, 219) |
| goldenrod | cmyk(0%, 24.3%, 85.3%, 14.5%) | rgb(218, 165, 32) |
| crimson | cmyk(0%, 90.9%, 72.7%, 13.7%) | rgb(220, 20, 60) |
| olivedrab | cmyk(24.6%, 0%, 75.4%, 44.3%) | rgb(107, 142, 35) |
| steelblue | cmyk(61.1%, 27.8%, 0%, 29.4%) | rgb(70, 130, 180) |
Read a row backwards to practice the subtractive logic: wherever an ink percentage is high, its opposing channel is low, and the K percentage scales everything that remains. After a few rows the direction of every CMYK edit — more magenta means less green, more black means less everything — becomes reflex rather than lookup.
How to use the CMYK to RGB Converter
- Enter the four ink percentages.
- The result updates live as you type – no convert button needed.
- Copy the value with the copy button, or switch the output format dropdown for other export shapes.
- Share the exact result: the page URL updates with your input, so the link reproduces it.
Frequently asked questions
How do CMYK inks become RGB light?
By inverting the subtractive model: R = 255×(1−C)×(1−K), G and B likewise from magenta and yellow. Ink absorbs light; the formula computes what reflects. It is the standard nominal conversion – honest about being profile-free.
Why does adding K darken all three RGB channels equally?
Because black ink absorbs across the whole spectrum in the idealized model – the (1−K) factor multiplies every channel. Real black inks are not perfectly neutral, one more line in the approximation ledger.
What RGB comes from 100% cyan alone?
rgb(0, 255, 255) – idealized cyan ink absorbs exactly the red light. Actual process cyan reflects a little red and prints closer to a teal; that gap between ideal and pigment is why press proofs exist.
Can I preview overprint or ink limits here?
No – overprint behaviour, dot gain and total-ink limits are physical press phenomena outside a nominal formula. This preview answers "roughly which screen color does this recipe aim at", nothing further.
Which way is safer: CMYK to RGB or RGB to CMYK?
CMYK to RGB is the tame direction – everything ink can print, a screen can display, so no gamut is lost. The reverse direction risks out-of-gamut surprises, which its converter flags in its notes.
Why do old brand guides list only CMYK?
They predate the web-first world – print was the primary medium and the press recipe was the definition. This converter is how those guides get a usable on-screen identity today, ideally confirmed against any surviving physical swatch.
Is the math done on my machine?
Yes – the four multiplications per channel run in your browser with plain JavaScript. No ink recipe you type is transmitted anywhere, nothing is stored, and the converter keeps working offline once the page has loaded.
