Autocad and the UP3D

If I make a 3D drawing in AutoCAD, convert it to a STL file and then load it in the 3d printer is this much too large and falling outside the margins of the printer. Does anyone know how to get it to the correct size. The drawing in AutoCAD scale 1 signed on 1. I can scale objects in the printer software I know but that I lose the right size.
Regards, John

Have you checked the units in AutoCad? Could be as simple as using inches instead of millimeters