Convert color from CMYK to OKLCH

CMYK to OKLCH converter

Convert CMYK to OKLCH for modern CSS.

Example: cmyk(0%, 58%, 79.2%, 0%)

OKLCH
See this color in all formats

About CMYK to OKLCH Converter

This takes a print color into modern CSS: CMYK to sRGB with the standard formula, then to OKLCH. It lets you build OKLCH-based palettes starting from a brand color that was only given in CMYK.

About the formats. CMYK describes a color as the share of cyan, magenta, yellow and black ink (each 0% to 100%) used to print it. Values are read as percentages, with or without the % sign, and the CSS name device-cmyk() is understood too. OKLCH is a perceptual color model built on Björn Ottosson's OKLab space: L is lightness from 0% to 100%, C is chroma (how vivid the color is, from 0 for grey up to about 0.32 inside sRGB) and H is the hue angle in degrees. Lightness tracks what the eye sees, so equal L values look equally light.

How exact is it? The conversion uses the plain mathematical formula, R = 255 × (1 − C) × (1 − K), with no color profile, so it will not match what a particular printer and paper produce. Every sRGB color has an exact OKLCH value. It is shown to four decimals for chroma and two for lightness and hue, so converting it back can differ by one step in a single channel for roughly 1 color in 1,000.

For example, cmyk(100%, 34.2%, 0%, 71.4%) in CMYK is oklch(29.38% 0.0656 238.47) in OKLCH. Every CMYK input gives a color inside sRGB, so unlike the other direction nothing is clipped here. The result is exactly the color shown in the swatch, written in OKLCH.

How to convert CMYK to OKLCH

  1. Type or paste a CMYK color, such as cmyk(100%, 34.2%, 0%, 71.4%), or choose a color with the picker.
  2. The OKLCH value, oklch(29.38% 0.0656 238.47) for that example, appears straight away.
  3. Press Copy to put the OKLCH value on your clipboard.
  4. Use the From and To menus at the top to switch to a different conversion, or open the all-formats page to see every format at once.

Frequently asked questions

How do I convert CMYK to OKLCH?

Type or paste a CMYK value such as cmyk(100%, 34.2%, 0%, 71.4%) and the OKLCH value, oklch(29.38% 0.0656 238.47), appears straight away. Use Copy to put it on your clipboard, or choose a color with the picker.

Is the result accurate to the printed color?

It is accurate to the screen color the formula gives, not to the ink. A color profile would change the starting point, and this converter has none.

Can I use the OKLCH lightness to compare brand colors?

Yes. Colors with a similar L look similarly light, which is useful when choosing text and background pairs with enough contrast.

Is converting CMYK to OKLCH exact?

The conversion uses the plain mathematical formula, R = 255 × (1 − C) × (1 − K), with no color profile, so it will not match what a particular printer and paper produce. Every sRGB color has an exact OKLCH value. It is shown to four decimals for chroma and two for lightness and hue, so converting it back can differ by one step in a single channel for roughly 1 color in 1,000.

Does CMYK to OKLCH keep transparency?

CMYK has no transparency, so the OKLCH result is always fully opaque.

Are my colors sent anywhere?

No. The conversion runs in your browser and nothing is uploaded.