Convert a cube to a square?

Sorry newbie question. Can u convert a cube object to a sphere object? And if so, how would i go about doing that? Thanks, im using version 2.56

There are two ways. First is through the Modifiers options and add Subdivision Surface, set that to at least 2 or 3. Second is in Edit mode, switch to edge, select all then press w-key and select subdivide smooth, do this a couple of times.

you can also subdivide the cube several times, and press alt+shift+s. (to sphere). That gives you a perfect sphere.

I’d subdivide the cube twice using w-subdivide. Then while in edit mode, from the mesh menu -> transform -> to sphere. Or shift-alt-s… After selecting this tool, the closer you move the mouse to the cube, the more round it will become, but it has it’s limits… so you may need to use it 3-4 times to get an actual sphere…