Calculating sperm count on a hemacytometer
The formula for calculating the sperm count when 5 small squares within the large center square are counted is:
Number of sperm counted in 25 squares on each of 2 sides x dilution factor/volume x 1000 = sperm/ml.
Example: 100 sperm are counted in the five small squares of one side of the hemacytometer, 110 sperm are counted in 5 small squares of the other. The dilution is 1:20.
Number of sperm in 25 squares on 2 sides = 210 x 5 = 1050
Sperm/ml = 1050 x 20 (dilution factor) divided by 0.2 mm3 x 1000 = 105 million sperm/ml.
