Delta E calculator: does anyone know where to find one?

I used to have a DeltaE calculator which I downloaded free from the Internet, but it does not seem to be available any longer.

The idea was to type in the Lab specification for two colour samples, then the calculator would come up with the difference between them expressed in units of Delta E.

I have found a calculator which requires Photoshop CS, but I cannot locate a free-standing version.