Delta E Calculator

Measure how different two colors look with Delta E 2000, CIE94, CIE76 and OKLab, with a plain-language reading of the result. Runs entirely in your browser. Nothing is sent to any server.

Colors

First color

Second color

Difference

#2563eb

#3b6fe0

What it means (ΔE 2000) Perceptible at a glance.

What is Delta E?

Delta E (ΔE) is a single number for how different two colors look to a person. Both colors are converted to the CIE Lab color space, which was designed around human vision, and their distance is measured there. The original 1976 formula is a straight-line distance; CIE94 and CIEDE2000 add corrections because people are more sensitive to some differences, such as in blues and in low-saturation colors, than to others. As a rule, a ΔE 2000 under 1 can't be seen, 1 to 2 needs a close look, and above 10 the colors are clearly different. This calculator gives all three, plus the distance in OKLab used by CSS Color 4.

Examples

Calculating Delta E in code with common libraries:

Python

from skimage.color import rgb2lab, deltaE_ciede2000

deltaE_ciede2000(rgb2lab(a), rgb2lab(b))

JavaScript

import chroma from "chroma-js";

chroma.deltaE("#2563eb", "#3b6fe0"); // CIEDE2000

library(farver)

compare_colour(decode_colour("#2563eb"), decode_colour("#3b6fe0"),
  "rgb", method = "cie2000")

JavaScript

import { differenceCiede2000 } from "culori";

const deltaE = differenceCiede2000();
deltaE("#2563eb", "#3b6fe0");

Use Cases

Checking color matches

Compare a printed or rendered sample with its target value and decide whether the difference is within tolerance, a common requirement in print and packaging.

Cleaning up a palette

Find colors in a stylesheet that are so close they should be unified into one token.

Verifying conversions

Measure how much a color shifted after compression, a gamut conversion or a format round trip.

Making distinct chart colors

Make sure the colors of a chart's series are far enough apart to be told apart at a glance.

Frequently Asked Questions

Which Delta E formula should I use?

CIEDE2000 for almost everything: it's the current CIE recommendation and matches perception best. CIE76 is simpler and still common in older tools, and CIE94 sits in between. Results from different formulas aren't directly comparable, so always say which one a tolerance refers to.

What tolerance is acceptable?

It depends on the use. Print and packaging specifications often ask for ΔE 2000 under 2 or 3, brand-critical colors sometimes under 1, while for UI work anything under about 2 is effectively the same color.

Why does swapping the colors change ΔE 94?

CIE94 weights the result by the chroma of the first color, the reference, so it isn't symmetric. CIE76, CIEDE2000 and the OKLab distance give the same value in both directions.

What is ΔE OK?

The straight-line distance in OKLab, the color space behind CSS oklch(). It's on a 0 to 1 scale instead of 0 to about 100, and CSS Color 4 treats 0.02 as just noticeable when mapping colors into a screen's gamut.

Is my data sent to a server?

No. Every formula runs in your browser with plain JavaScript. Nothing you enter is transmitted or stored.