Fill both sides of the hemacytometer. Focus on the large center square with the 20X objective. The counting area consists of five small squares in the large center square. The squares usually counted are the four corner squares and the center square, all of which are marked R. A minimum of 100 sperm should be counted in the five small “R” squares. If the number of sperm is low then 10 squares or all squares may be counted to obtain the 100 per side.
Count both sides of the hemacytometer and take the average of the two counts to calculate the actual count per ml.