It is well known that workspace of fixed-base manipulators is dependent on the geometry of its links. This paper presents studies on the workspace of free-floating manipulators. A unique property of free-floating manipulators is that the workspace is not only a function of links' geometry but is also dependent on the mass distribution. This paper addresses the question of how to find the workspace and boundaries of free-floating open and closed-chain planar manipulators. Further, the effect of mass distribution on the workspace of the manipulator is studied and guidelines for design of the manipulator are suggested.