LAB to LCH Converter

Convert CIELAB (L*a*b*) values to cylindrical LCH, giving lightness, chroma, and a hue angle in degrees. Chroma and hue make it easier to adjust a color without shifting its lightness.

lab

lch

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Quick Presets

Common colors as CIELAB (D65) valuesNeed LAB to RGB?

Input

Enter CIELAB values to convert to cylindrical LCH (lightness, chroma, hue).

Lightness (L*)

a* (Green–Red)

Green (-128)Red (+127)

b* (Blue–Yellow)

Blue (-128)Yellow (+127)

How it works: Converts CIELAB to LCH(ab): L* stays the same, chroma is the distance sqrt(a*^2 + b*^2) from the neutral axis, and hue is atan2(b*, a*) in degrees from 0 to 360.

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What is LAB to LCH Converter?

The LAB to LCH Converter turns CIELAB (L*a*b*) values into LCH: lightness, chroma, and hue angle. Enter L*, a*, and b* and read L*, C*, and h in degrees with a color preview. The tool converts rectangular LAB coordinates into polar ones.

How does LAB to LCH Converter work?

LCH(ab) uses the same lightness as CIELAB. Chroma C* is the distance from the neutral axis, the square root of a* squared plus b* squared. Hue h is the angle atan2(b*, a*) converted to degrees and wrapped into 0 through 360.

For neutral colors where a* and b* are both zero, hue has no meaning and the tool reports 0. The preview swatch renders the LAB color as sRGB, with out-of-gamut channels clamped.

Key Features

Converts L*a*b* to LCH(ab)
Reports chroma C* and hue angle h in degrees
Wraps hue into 0 through 360
Reports hue as 0 for neutral colors
Live color preview of the input color
Four preset colors with matching LAB values

Common Use Cases

When and why you might need this tool

Adjust hue without changing lightness
Read the hue angle and chroma of a color before you rotate or scale them.
Describe colors in perceptual terms
Express a LAB measurement as lightness, chroma, and hue for a report.
Compare color families
Check whether two colors share a hue angle but differ in chroma.
Test a conversion library
Compare your own atan2 and square root code against a reference result.

How to Use This Tool

Step-by-step guide to get the best results

Enter L, a, and b*

Use the sliders or type values. L* runs from 0 to 100, and a* and b* from -128 to 127.

Review the preview

The swatch shows the color as sRGB.

Copy the LCH values

Read L*, C*, and h or copy the lch() string.

Read chroma and hue

C* is the distance from the neutral axis and h is the hue angle in degrees from 0 to 360.

Pro Tips

1
A hue of 0 degrees points toward +a*, which is red-magenta, and 90 degrees points toward +b*, which is yellow.
2
Colors with low chroma, under about 5, have unstable hue angles. Small LAB changes can swing the hue a lot.
3
The tool assumes D65 LAB. CSS lab() and lch() values use a D50 white point and will not match.
4
Use the LAB to RGB Converter if you also need the screen color.
5
Values are shown to two decimal places. Keep the full precision in your own calculations.

Frequently Asked Questions

How do you convert LAB to LCH?

Keep L* as is, compute chroma as the square root of a* squared plus b* squared, and compute hue as the arctangent of b* over a* in degrees. This tool does this for you.