This repository contains the CIE (International Commission on illumination) L* a* b* (also known as CIELAB) distance metric (ΔE*) formulas ΔE_1976, ΔE_CMC, ΔE_1994 and ΔE_2000 in VBA for Excel.
Kindly see the comments in the txt file for an optimal use.
The implementation of the ΔE_2000 formula has been made possible thanks to the resources published by Mr. Gaurav Sharma, one of the developers of the formula, on his institutional website, which was very helpful given the real complexity of the algorithm. In the same vein, the Wikipedia page is full of convenient notes.
As an example, this is a table with results where, for aesthetics, the decimals were truncated:
