CIE LAB Color Converter

Convert between CIE LAB (perceptual) and RGB/Hex color spaces with Delta E distance.

Tested tool guide Tested browser tools Checked August 16, 2026

What CIE LAB Color Converter does, with a checked example

CIE LAB Color Converter translates a color between CIE L*a*b* coordinates and RGB or six-digit Hex notation. LAB describes lightness and two opponent color axes, while Hex records the same three channels used by RGB. The tool can also compare two LAB colors and report their Delta E distance. A common surprise is that LAB does not identify an RGB color space or reference white by itself. Different conversion assumptions, gamut handling, and rounding can therefore produce different RGB values for the same LAB coordinates.

Worked example

A concrete input and expected output from the current implementation.

Input

Color 1 Hex: #000000
Color 2 Hex: #000000

Expected output

Color 1 RGB: 0, 0, 0; LAB: L*=0, a*=0, b*=0
Color 2 RGB: 0, 0, 0; LAB: L*=0, a*=0, b*=0
Delta E: 0

Black has zero RGB channel values and maps to zero lightness with neutral LAB axes. The two LAB points are identical, so their distance is exactly zero under every standard Delta E formula.

How the result is produced

Converting color coordinates

In the LAB direction, the converter reports L* for lightness, a* for the green-to-red axis, and b* for the blue-to-yellow axis. In the RGB direction, it produces three bounded channel values and their #RRGGBB representation. Hex is an encoding of the RGB channels, not an independent color space.

Measuring LAB distance

For two colors, Delta E summarizes the separation between their LAB coordinates as one number. Identical coordinates have a distance of zero, and larger distances generally indicate greater color difference. The number is meaningful only when both colors use compatible LAB conditions. Its interpretation also depends on which Delta E formula the tool identifies.

Good uses

Convert a measured or supplied LAB swatch into an RGB and Hex approximation for a screen-oriented design.
Recover LAB coordinates from a Hex color before comparing it with a product, paint, textile, or print reference.
Check whether two LAB samples are identical or quantify their reported Delta E separation.

Limits and checks

An RGB or Hex result may only approximate a LAB color that falls outside the destination RGB gamut.
LAB values are ambiguous without compatible reference-white and observer conditions; results from different profiles should not be compared blindly.
Do not treat an unlabeled Delta E value as interchangeable with CIE76, CIE94, or CIEDE2000; those formulas can return different distances.

Common questions

Why does another LAB converter return different RGB values?

LAB-to-RGB conversion requires assumptions beyond the three LAB numbers, including a reference white and a destination RGB space. Chromatic adaptation, gamut treatment, channel rounding, and clipping can also affect the displayed result. If the tools do not state matching conditions, their RGB or Hex outputs need not agree even when both accept the same LAB input.

Does a small Delta E guarantee that two printed samples will look identical?

No. Delta E compares color coordinates according to a particular formula, but an observed match can also depend on illumination, substrate, ink, surface texture, measurement geometry, and the viewer. Use the value as a colorimetric comparison, not as a universal pass or fail decision. Confirm which Delta E formula and measurement conditions apply.

References and verification

The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.