The full grid on a hemocytometer contains 9 squares, each of which is 1 micro meter (mm) square. Large cells are counted using the four large corner squares (and the middle one).
For a dense suspension of small calls, the four 1/25 sq. mm corners plus the middle square and the central square are used.
It consists of 9 large squares, each measuring 1 x 1 mm, with the depth of chamber of 0.1 mm. Each square has a total volume of 0.1 mm^{3} or 10^{4}cm^{3}. The central square is divided into 25 small squares with triple lines and four corner squares divided into 16 small squares.
Each large square has a surface area of 1.0mm^{2}, and a chamber depth of 0.1mm. There are 1000 mm^{3} per ml, each large square represents a volume of 0.0001ml, that equates to 1/ 0.0001ml = 10,000 = (10^{4}). The volume factor is 10,000.
