The first step in the floor-planning phase of a design is to build the power-grid. Though it may seem simple, in reality, power grid design is one of the most important and challenging activities in floor-planning. The most critical step is to decide the width of the power and the ground stripes and the spacing between these stripes. This paper discusses the techniques to finalize the width of, and the spacing between, the power and the ground lines. These techniques have been converted into user friendly mathematical expressions that simplify the process of power grid design significantly.