Cost of Fibre or Yarn : The cost of the fibre will depend largely on its generic type - cotton, linen, wool, silk, rayon, nylon, polyester, polyester cotton blend etc, and also its quality. The Yarn cost will depend on the count of the yarn -- finer the yarn, more expensive it will be. Number of fine filaments used in making the yarn will also affect the cost.
Relation between count and GSM:Count means the thickness of the fabric.The thinner the fabric the better the quality therefore the higher the cost and viceversa. GSM (grams/sq mt) of the fabric. GSM is directly dependent on the EPI and PPI or construction of the fabric and is inversely proportional to the count of the yarn. Relation between GSM and cost is a little complex. For the same variety of the fabric, as the GSM increases the cost increases.When the yarn becomes very fine and there is a variation in picks per inch in the fabric, then the cost of spinning and weaving plays a more important role than the GSM and even when the GSM is similar, the cost of voile fabric with finer yarns and more picks per inch is more.
Weight of the fabric is the weight of warp and weft which can be calculated by the formula below:
Weight of warp in grams/sq mt of fabric = EPI x 0.6 / Count of Warp = A
Weight of weft in grams/sq mt of fabric = PPI x 0.6 / Count of Weft = B
GSM = A+B