Yarn count is a measure of a linear density of a yarn so it reflects the thickness of the yarn. Generally, there are 2 yarn count systems which are indirect count system and direct count system.
a. Indirect Count
1. Cotton Count --- unit "S"
1 S = Length of 840yards in a weight 1 lb (840yards/1lb), Hank number=840yards
2. Metric Count --- unit "Nm"
1 Nm= Length of 1000m in a weight 1kg (1000m/1kg), Hank number=1000m
3. Worsted Count
1 unit = Length of 560 yards in a weight 1lb (560yards/1lb), Hank number=560yards
Indirect Yarn Count= L/HxW where L is length of a yarn, H is Hank number and W is weight of a yarn
b. Direct Count
1. Tex --- unit "Tex"
1 Tex = Weight 1g in a length 1000m (1g/1000m), Hank number =1000m
2. Denier--- Unit "D"
1 D = Weight 1g in a length 9000m (1g/9000m), Hank number = 9000m
Direct Yarn Count= HxW/L where L is length of a yarn, H is Hank number and W is weight of a yarn
