The full grid on a hemocytometer contains nine squares, each of which is 1 mm2 (Figure 3). The central counting area of the hemocytometer (Figure 3B) contains 25 large squares and each large square has 16 smaller squares. When counting, count only those cells on the lines of two sides of the large square to avoid counting cells twice (Figure 3G). Suspensions should be dilute enough so that the cells or other particles do not overlap each other on the grid, and should be uniformly distributed.