ProKon for Windows

It supports over 400,000 conversions, in 26 different categories, both to and from the SI (metric), Imperial (English), and U.S. Customary systems. Many specialized ancient and archaic units are also available.

ProKon provides a periodic table of the elements (with pertinent data on each element) and many mathematical formulas, along with the density of over 625 different materials -- some common and some not so common.

Context sensitive help is easily accessed throughout the program, and you can easily copy converted values to the Clipboard for pasting into other applications. ProKon features an additional 55 modules for a wide variety of scientific, construction and educational calculations.