Advanced Converter 3.5   
by Masterra   

Advanced Converter is a professional program for conversion between units of measurements. The program contains more than 1700 units divided in 66 groups. It is very simple to add new units and custom groups of units. You may arrange groups and units in according with personal preferences.

An in-depth help section is available which can explain how to use the program, what buttons do, and much more. This is a wonderful converter with many different features.
A must for everyone who works with numbers and measurement systems.