As an instrumentation engineer we have to do a lot of unit conversion. I got a very effective tool converting units. It is a not a software. It is an excel sheet. No need to install it but Microsoft office software must be installed in your computer for opening the tool.
You can convert the following units.
*Length
*Volume
*Molar power rate
*Volumetric flow rate
*Pressure
*Power
*Energy
*Mass
*Density
*Area
*Dynamic viscosity
*Kinematics viscosity
*Mass flow rate
*Heat transfer coefficient
*Thermal conductivity
*Heat flux
*Specific energy
*Specific Heat
Download the Unit conversion tool.
I got the tool from Internet. If you are having such tools, share it..