This simple calculator takes a measurement and rounds it to nearest standard English units.
I have used this when building my CAD designs. My designs in CAD have arbitrary, messy measurements (i.e. 1.734854" vs. 1 3/4"), and in order to measure and mark my raw materials I need to convert it to standard English units. I use this calculator for the conversion, and to determine whether the rounding is sufficiently accurate. My rule of thumb is to keep the difference between the exact and rounded measurements less than 10 thousandths of an inch. Depending on the precision requirements, more or less difference can be tolerated.