The grid-clustering algorithm is the most important type in the hierarchical clustering algorithm. The grid-based clustering approach considers cells rather than data points. In grid-based clustering all the clustering operations are performed on the segmented data space, rather than the original data objects. Grid-based methods are highly popular compared to the other conventional models due to their computational efficiency but to find optimal grid size is a key feature in grid-based clustering algorithm. There exists some algorithm in that they achieve optimal grid size but in real life data can be dense or sparse.