What is the valid input range for X, Y, Z?

For the D65 sRGB reference white, the normalized range is X=0–0.95047, Y=0–1.00000, Z=0–1.08883. Values above these bounds are accepted; the resulting LAB values will simply exceed the typical 0–100 / ±128 range. Some workflows express XYZ in percentage form (0–100); this tool uses the 0–1 normalized scale.

What reference white does this tool use?

D65 (standard daylight, 6500 K) with Xn=0.95047, Yn=1.00000, Zn=1.08883. D65 is the standard illuminant for sRGB and the most common choice for web, display, and print colorimetry.

What is the typical range for L*, a*, and b*?

L* ranges from 0 (black) to 100 (white reference). a* and b* are theoretically unbounded but in practice range roughly from −128 to +127 for sRGB-gamut colors. Positive a* is red, negative a* is green. Positive b* is yellow, negative b* is blue.

What does X=0.4124, Y=0.2126, Z=0.0193 convert to?

Those are the XYZ D65 coordinates of sRGB red. They convert to approximately L*=53.23, a*=80.11, b*=67.22 — a highly saturated red in CIELAB.

How does LAB differ from XYZ?

CIE XYZ is a linear, device-independent color space based on cone response functions. CIELAB (L*a*b*) is a non-linear transformation of XYZ designed to be perceptually uniform — equal numerical distances in LAB space correspond more closely to equal perceived color differences.

Does this tool send data to a server?

No. All conversion math runs entirely in your browser using JavaScript. No data is transmitted anywhere.

XYZ to LAB Converter

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

Enter CIE XYZ tristimulus values and instantly get the equivalent CIE L*a*b* color with a live swatch and formula breakdown.

CIE XYZ Input

X 0.4124

Y (Luminance) 0.2126

Z 0.0193

rgb(255, 0, 0)

CIE Lab* Output

L* (Lightness)

a* (Green–Red)

b* (Blue–Yellow)

Conversion Steps

1 XYZ input: X=0.4124, Y=0.2126, Z=0.0193
2 Divide by D65 white (Xn=0.95047, Yn=1.00000, Zn=1.08883): xr=0.4339, yr=0.2126, zr=0.0177
3 Apply CIE f(t): t^1/3 if t > 0.008856, else 7.787·t + 16/116: fx=0.7576, fy=0.5966, fz=0.2603
4 L*=116·fy−16, a*=500·(fx−fy), b*=200·(fy−fz): L*=53.23, a*=80.11, b*=67.22

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Summary

Enter CIE XYZ tristimulus values and instantly get the equivalent CIE L*a*b* color with a live swatch and formula breakdown.

How it works

Enter X, Y, and Z values using the number inputs or sliders (normalized range 0–1, where D65 white is X=0.95047, Y=1.00000, Z=1.08883).
Each XYZ channel is divided by the corresponding D65 reference white value to produce normalized ratios xr, yr, zr.
Each ratio is passed through the CIE f() function: f(t) = t^(1/3) if t > 0.008856, else f(t) = 7.787*t + 16/116.
L* = 116 * f(yr) − 16, a* = 500 * (f(xr) − f(yr)), b* = 200 * (f(yr) − f(zr)).
XYZ is also converted to sRGB via the D65 matrix and gamma encoding to render the live color swatch.
Copy any individual LAB value or the full lab() CSS string with one click.

Use cases

Convert spectrophotometer XYZ measurements into perceptually uniform CIELAB values.
Compute delta-E (color difference) between two colors by converting both to LAB.
Verify that an XYZ color specification maps to expected LAB values in a color management workflow.
Translate ICC profile XYZ connection space values to LAB for quality control.
Explore the LAB gamut by adjusting XYZ sliders and observing how L*, a*, b* change.
Generate CSS lab() values for modern browsers from device-independent XYZ data.
Cross-reference paint, ink, or textile XYZ specifications with their LAB equivalents.
Build color palettes grounded in perceptually uniform LAB spacing.

Frequently Asked Questions

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