Count is a numerical expression that indicates the fineness or coarseness of yarn. There are several systems used to express yarn count including indirect, direct, and universal (Tex) systems. The indirect system expresses count as the length of yarn per unit of weight, while the direct system expresses count as the weight of yarn per unit of length. Common conversion formulas are provided between count systems like English, metric, denier, and Tex. Instruments like the quadrant balance, Knowles balance, Beesleys balance, and measuring drum are used to determine yarn count.