This is a measure of the fineness (thin-ness) of cotton. Typically, it is calculated using the English count method, which measures the number of hanks (840 yards) in a pound of cotton. 100’s cotton has 100 hanks in one pound, which means 84,000 yards equals one pound of cotton. The higher the number, the finer the cotton. 100’s cotton is categorized as a fine count, with anything above 80 being considered such.