The length category definitely is the most frequently used category.
This app can generate results in decimal points output and imperial system format, (ft. in. and fraction) at the same time, and you won't find them from other units converters.
It consists of three calculators:
One master Units conversion calculator.
Two other calculators with measuring tape imperial system designed with high precision levels from 1/32\" to 1/256\", plus the results can be emailed.

Ideal for engineers, architects, designers, fabricators, estimators and students.
Especially for Aluminum fabrication where they have to dealt with dimensions all the time.

Available categories:
Length, Area, Volume, Mass, Pressure, Linear Velocity, Angular Velocity,
Acceration, Energy, Power, Density, Thermal conductivity,
Thermal conductance, Heat flow, Temperature, Data storage,
Angles, Fuel consumption(US), Fuel consumption(UK), Time,
Flow rate, Force, Torque, Cook Measurement.