WinConverter 2.1   
by OneMir   

WinConverter is a rather straightforward application designs to provide as simple an interface as possible for performing unit conversion. WinConverter 2.1 is pre-configured to convert 1400 units in 76 categories. If you find WinConverter is missing a unit you need, it's very easy to add custom units or categories.

The categories include:
Mass, Length, Time, and Volume.
Acceleration - Linear, Area, Data Storage, Data Transfer, Energy, Flow, Force, Numbers, Power, Pressure, Temperature, Velocity, Acceleration - Angular, Angle, Calorific Value, Concentration - Liquid Solution, Concentration - Molar, Density, Digital Image Resolution, Entropy, EU Currency, Flow - Mass, Flow - Molar, Frequency Wavelength, Fuel Efficiency, Heat Capacity, Heat Flux Density, Heat Transfer Coefficient, HVAC Efficiency, Chemical - Henry's Law, Illumination, Illumination - Luminous Intensity, Latent Heat, Luminance, Mass Flux Density, Moment of Inertia, Permeability, Radiation, Radiation - Absorbed Dose, Radiation - Activity, Radiation - Exposure, Sound, Specific Heat, Specific Volume, Surface Tension, Temperature Interval, Thermal Conductivity, Thermal Expansion, Torque, Typography, Velocity - Angular, Viscosity - Dynamic, Viscosity - Kinematic, Volume - Dry, and Volume - Lumber.

Electrical:
Capacitance, Charge, Conductance, Conductivity, Current, Electric Field, Inductance, Linear Current Density, Linear Charge Density, Magnetic Flux, Magnetic Flux Density, Magnetomotive Force, Resistance, Resistivity, Surface Current Density, Surface Charge Density, and Volume Charge Density.