A partitioning method for partitioning a group of power-ground (PG) cells is disclosed. The method includes forming a first partition by selecting at least one in-boundary PG cell from the group of PG cells, adding at least one out-boundary PG cell from the group of PG cells into the first partition, forming a second partition by selecting the remaining in-boundary PG cells and the remaining out-boundary PG cells in the group of PG cells, calculating the total area of the in-boundary PG cells in the first partition, calculating the total area of the out-boundary PG cells in the first partition, calculating the total area of the in-boundary PG cells in the second partition, calculating the total area of the out-boundary PG cells in the second partition, and calculating the difference between the total areas of in-boundary PG cells in the first partition and the out-boundary PG cells in the first partition.