Why is the HWB result approximate?

CMYK and HWB occupy different color gamuts. CMYK describes print pigments while HWB is based on the RGB screen model. The conversion passes through RGB as an intermediate step, so some print colors may not display identically on screen.

What is the Key (K) channel in CMYK?

K stands for Key, which represents black ink. A separate black channel produces deeper blacks and reduces overall ink cost compared to mixing equal amounts of Cyan, Magenta, and Yellow.

How is CMYK converted to HWB?

The conversion has two steps. First, CMYK is converted to RGB: R = 255 × (1−C/100) × (1−K/100), G = 255 × (1−M/100) × (1−K/100), B = 255 × (1−Y/100) × (1−K/100). Then RGB is converted to HWB by computing Whiteness = min(R,G,B)/255, Blackness = 1−max(R,G,B)/255, and Hue via the standard HSV hue formula.

HWB stands for Hue, Whiteness, Blackness. Hue is the color angle (0–360°), Whiteness is the amount of white mixed in (0–100%), and Blackness is the amount of black mixed in (0–100%). It is part of CSS Color Level 4 and is supported in all modern browsers.

What does K=100 produce in HWB?

K=100 with any C, M, Y values produces pure black: hwb(0 0% 100%). All channels at 0 produce pure white: hwb(0 100% 0%).

Does this tool send my data anywhere?

No. All conversion math runs entirely in your browser using JavaScript. No data is sent to any server.

CMYK to HWB Converter

Name: CMYK to HWB Converter
Availability: InStock
Author: Nham Vu

Enter CMYK percentages and instantly get the equivalent HWB values with a live color preview swatch.

CMYK Input

Cyan (C) 0%

Magenta (M) 45%

Yellow (Y) 100%

Key / Black (K) 0%

rgb(255, 140, 0)

HWB Output

Hue (°)

Whiteness (%)

Blackness (%)

Conversion Steps

1 CMYK → RGB: R=255, G=140, B=0
2 RGB → HWB: hwb(33 0% 0%)

Copied!

Summary

Enter CMYK percentages and instantly get the equivalent HWB values with a live color preview swatch.

How it works

Enter Cyan, Magenta, Yellow, and Key (Black) percentages (0–100) in the input fields or sliders.
The tool first converts CMYK to RGB using the standard formula: R = 255 × (1 − C/100) × (1 − K/100), and similarly for G and B.
RGB is then converted to HWB: Whiteness = min(R,G,B)/255, Blackness = 1 − max(R,G,B)/255, and Hue is the HSV hue angle.
The HWB output — Hue (°), Whiteness (%), and Blackness (%) — updates instantly.
A color swatch previews the exact resulting color.
Click "Copy HWB" to copy the hwb() CSS string to your clipboard.

Use cases

Translate print-spec CMYK colors into CSS-ready HWB values.
Cross-reference brand color specifications between print and web.
Convert CMYK values from design files into HWB for modern CSS stylesheets.
Validate that a print color matches the intended on-screen appearance.
Build HWB color palettes from existing CMYK brand guides.
Understand how whiteness and blackness relate to a given ink mix.
Generate hwb() values for CSS Color Level 4 without a preprocessor.
Quickly estimate the hue produced by a particular CMYK combination.

Frequently Asked Questions

Related tools

Cmyk To Hsl Rgb To Hwb Hsl To Hwb

Last updated: 2026-05-28 · Reviewed by Nham Vu