The work area (user interface) > Workplanes > Workplane settings
  
Workplane settings
Workplane settings control the default colors, size, border, grid, and resolution of all new workplanes you create. To change the properties of an existing workplane, see the Workplane properties link below.
You can set the minimum size for new workplanes. The workplane will grow as you add profiles or construction geometry. If you create a new workplane without specifying a position, the lower left corner of a new workplane is positioned at 0,0 minus 10% of the default size. For example, if the default size is 100, then the lower left corner of the workplane is positioned at -10,-10.
For more information on Workplane Settings, see 3D Object Settings