Firslty, what's the yarn count? The yarn count expresses the thickness of the yarn, and must be known before calculating the quantity of yarns for a known length of fabric. The yarn count number indicates the length of yarn in relation to the weight.

Determine the yarn count of your unknown cones of yarn with a simple set of measurements and calculations. The yarn count is a measurement of how thick yarn is. Yarn with a lower count is thicker, while yarn with a higher count is finer. To calculate the yarn count you first need to know what fiber your yarn is made from, such as wool, cotton or linen.

How to calculate the yarn count?
Measure the length of the weighed yarn using the measuring tape.
Convert the total length into the appropriate unit for the type of yarn. For example, the unit for cotton is the hank, which is 840 yards. So, a cotton yarn with 8,400 yards in a pound would be 10 hanks. This conversion is approximate and should come to a round number. Choose the number closest to the conversion. So, a yarn with 7,980 yards in a pound would still come to 10 hanks. Count the number of plies, or strands, in the yarn. The yarn count is the number of plies/number of units. For example, if the cotton yarn is two ply, its count is 2/10 cotton.

When a yarn is plied, that is, when two yarns of identical count are twisted together, the yarn is twice as thick, and therefore the length of yarn per kg is halved. The numbering of the yarn states both the count of the single component and the number of components that make up the ply.

E.g.: 2/10’s cotton; the length of this yarn would be 10 x 840 divided by 2 = 4200 yards per lb. And it can be seen that a 2/20 yarn varies greatly in length depending on whether it was measured as cotton, linen, wool, or worsted.