Color distance calculator
Enter two colors in HEX, rgb(), hsl() or as CSS names. The calculator converts them to CIE Lab and gives the difference (Delta E) by three formulas, with CIEDE2000 as the main value.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Enter color A and color B.
- Read the CIEDE2000 value (the main one), plus CIE76 and CIE94.
- Use the rule of thumb to judge whether the colors will look the same.
How it works
Both colors are converted from sRGB to CIE L*a*b* (D65). CIE76 is the straight distance √(ΔL² + Δa² + Δb²). CIE94 (graphic arts weights) divides the chroma and hue differences by terms that grow with the chroma of the reference color. CIEDE2000 adds corrections for lightness, chroma and hue, a rotation term for blues and a boost for greys, following Sharma, Wu and Dalal (2005).
Example
Black #000000 and white #ffffff are 100 apart in all three formulas. Pure red and pure green are 170.57 apart by CIE76, 73.43 by CIE94 and 86.61 by CIEDE2000, which shows how CIE76 exaggerates strong colors. The default pair #3366cc and #3a6fd0 has a CIEDE2000 value of 3.19: visible at a glance.
Tips
- Compare colors on the same screen: calibration and surroundings change what you see.
- Use CIEDE2000 for matching brand colors and print proofs.
- A small ΔE does not mean the colors have the same contrast against text; use a contrast checker for that.
Frequently asked questions
What is Delta E?
Delta E (ΔE) is a number for the difference between two colors. It is the distance in a color space built so that equal distances should look about equally different. A larger number means a bigger visible difference.
Which formula should I trust?
CIEDE2000 is the most accurate for human vision and the one the tool shows first. CIE76 is a plain distance in Lab and overstates differences in saturated colors. CIE94 sits in between and, because it treats the first color as the reference, gives a slightly different result if you swap the colors.
What counts as a noticeable difference?
As a common rule of thumb, a ΔE00 below 1 is not seen by most people, 1 to 2 only on a close look, 2 to 10 at a glance, and above that the colors are clearly different. These limits vary with viewing conditions and the person, so they are not a standard.
How are the colors converted?
sRGB is converted to linear light, then to XYZ and to CIE Lab with the D65 white point. Other tools may use a D50 white point or a different RGB matrix, so their numbers can differ slightly.
How was CIEDE2000 checked?
The implementation is tested against the published test pairs of Sharma, Wu and Dalal (2005), which are the standard way to find mistakes in the formula, including its hue and sign rules.