What is the CIE LAB color space?

CIE LAB (also written L*a*b*) is a perceptually uniform color space defined by the International Commission on Illumination. L* represents lightness (0 = black, 100 = white), a* the green-to-red axis, and b* the blue-to-yellow axis.

Why might the result show "out of gamut"?

LAB covers a wider color range than sRGB. Colors outside the sRGB gamut will be clamped to the nearest valid value (0–255 per channel). The tool flags this so you know the output is an approximation.

What illuminant does the converter use?

The conversion uses the D65 standard illuminant (daylight 6500 K), which is the reference for sRGB and the most common choice for web and screen work.

What does the alpha value control?

Alpha controls opacity. A value of 1 means fully opaque, 0 means fully transparent. It is independent of the LAB-to-RGB conversion and is simply appended to produce the final rgba() string.

Is this conversion lossless?

The math is lossless for colors inside the sRGB gamut. Colors outside the gamut are clamped, which is lossy. The 8-bit rounding to integer RGB values also introduces a small rounding error.

LAB to RGBA Converter

Name: LAB to RGBA Converter
Availability: InStock
Author: Nham Vu

Enter CIE LAB (L*, a*, b*) values and get the corresponding RGBA color with a live preview.

LAB Input Values

L* — Lightness (0 to 100)

a* — Green / Red axis (-128 to 127)

b* — Blue / Yellow axis (-128 to 127)

Alpha (0 to 1)

Quick Presets

Color Preview

RGBA Output

CSS rgba()

rgba(128, 128, 128, 1)

HEX (with alpha)

#808080FF

128

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Summary

Enter CIE LAB (L*, a*, b*) values and get the corresponding RGBA color with a live preview.

How it works

Enter the L* value (0 to 100) for lightness.
Enter the a* value (-128 to 127) for the green-red axis.
Enter the b* value (-128 to 127) for the blue-yellow axis.
Adjust the alpha slider (0 to 1) if transparency is needed.
The tool converts LAB through XYZ to sRGB in real time.
Copy the resulting RGBA value to use in your code or design tool.

Use cases

Convert perceptually uniform LAB colors to CSS-ready RGBA values.
Translate colors from design specs or scientific datasets into web formats.
Verify that a LAB color falls inside the sRGB gamut.
Generate RGBA values for UI components from brand color guidelines.
Debug color pipeline conversions in graphics or image-processing projects.
Quickly preview how a LAB color looks before applying it to a design.

Frequently Asked Questions

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