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CMYK to RGB Converter

Convert a CMYK print color value into RGB for screen display.

Result

RGB
rgb(61, 196, 245)
Hex
#3DC4F5

This is the standard naive CMYK-to-RGB formula used for screen preview. Real printed color also depends on ink, paper and printer color profiles, so a true print proof can look noticeably different from this on-screen approximation.

About the CMYK to RGB

This calculator converts a CMYK print color, expressed as cyan, magenta, yellow, and key/black percentages, into the RGB and hex values used for screen display. It is intended for designers moving a color specified for print into a digital mockup or web page.

How It Works

Enter values from 0 to 100 for cyan, magenta, yellow, and key (black), and the tool applies the standard subtractive-to-additive conversion formula to each channel to produce a 0-255 RGB value, then formats that same RGB value as a six-digit hex code.

R = round(255 x (1 - C) x (1 - K)); G = round(255 x (1 - M) x (1 - K)); B = round(255 x (1 - Y) x (1 - K)), where C, M, Y, K are entered as fractions between 0 and 1

Formula & Methodology

Each CMYK input is first clamped to the 0-100 range and divided by 100 to get a fraction between 0 and 1. The RGB formula works by treating each channel's cyan/magenta/yellow value as how much of that primary's complementary light is subtracted, then applying the key (black) value as an overall darkening multiplier on top: (1 - C) represents how much red light remains after cyan absorption, and multiplying by (1 - K) darkens it proportionally to the black percentage. The three resulting fractions are each multiplied by 255 and rounded to whole numbers, then converted to a two-digit hexadecimal pair per channel to build the hex code.

Examples

A print blue swatch

Entering C=75%, M=20%, Y=0%, K=4% returns RGB(61, 196, 245) and hex #3DC4F5, an approximate on-screen preview of that print color.

Rich black for text

Entering C=0%, M=0%, Y=0%, K=100% returns RGB(0, 0, 0) and hex #000000, since a 100% key value zeroes out all three channels regardless of the other inputs.

Advantages

  • Gives designers an immediate RGB and hex equivalent for a CMYK color without needing print-specific software.
  • Applies the clamp to valid percentage ranges automatically, preventing invalid negative or over-100 inputs from breaking the math.
  • Outputs both RGB and hex formats in one step, covering the two formats most commonly needed for web and app design.

Common Mistakes

  • Treating the converted RGB/hex value as a guaranteed print match, when it is only an approximation without a real ICC color profile.
  • Entering CMYK percentages as decimals (like 0.75) instead of whole percentages (75), which would understate every channel.
  • Assuming a high key (black) percentage alone determines darkness while ignoring how it multiplies against the other three channels.

Edge Cases to Watch For

  • Any CMYK input outside the 0-100 range is clamped before conversion, so entering 150 for cyan is treated the same as entering 100.
  • A key/black value of 100 forces all three RGB channels toward 0 regardless of the C, M, and Y values, producing black.
  • This is a naive, uncalibrated formula meant for on-screen approximation; it does not account for ink, paper stock, or printer color profiles, so the actual printed color can look noticeably different from the RGB preview.

Common Use Cases

  • Graphic designers translating a brand's print color specification into a matching web or app color.
  • Print shop staff giving clients a rough on-screen preview of how a CMYK design will appear before proofing.
  • Students and hobbyists learning how subtractive (CMYK) and additive (RGB) color models relate to each other.
Written & fact-checked by the Calculateus TeamLast updated August 5, 2026How we verify our formulas

Frequently asked questions

Why does a printed CMYK color look different from its RGB screen preview?

Screens emit light (RGB, additive color) while printers use reflected light off ink and paper (CMYK, subtractive color) - actual ink absorption, paper texture and printer color profiles affect the final result in ways the basic conversion formula can't capture, so professional print work relies on calibrated color profiles rather than this simple math.

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Conclusion

This tool applies the standard textbook CMYK-to-RGB formula, useful as a fast approximation for cross-referencing print and screen colors. For color-critical print production, an actual proof or calibrated color profile remains necessary since this conversion does not model ink or paper behavior.

References