Metric Count
Metric Count is a constant-weight yarn count that expresses the length of yarn per a given weight in meters, and is a unit in which a larger number indicates a finer yarn.
Contents6 sections
Definition and Overview
Metric count is written as Nm and indicates how many meters of yarn there are per gram. For example, Nm 1 means 1 meter per gram, and the larger the number, the longer the yarn for the same weight, so the yarn becomes finer.
It is also called wool count or the common formula count, and is mainly used when indicating the thickness of spun yarn. The basic notation shows the count of a single yarn, but for yarns made by twisting multiple yarns together, it is necessary to check the count notation before and after twisting.
Hand feel and Effect on Fabric
In general, finer yarns with a higher metric count tend to create a delicate, light appearance, and when designed with a higher density, they can lead to smoothness and an elegant look. However, fineness alone does not determine softness or strength.
Thicker yarns with a lower count tend to create a stronger yarn presence, fullness, and a more rustic appearance. The actual hand feel, warmth retention, durability, and sheerness should be judged together with the type of fiber, twist, whether it is single yarn or plied yarn, structure, density, and processing.
Main Applications
Metric count is used to check the specifications of spun yarns, including wool, and woven fabrics and knits made from those yarns. Fine counts are used for the delicate expression desired in shirts, blouses, lightweight knits, and suiting fabrics, while thicker counts are used for sweaters, tweed-like fabrics, and heavy cut-and-sew items.
However, applications and seasons cannot be determined uniformly from the count alone. Even with the same count, if the material differs, moisture absorption and warmth retention will change, and the thickness and applications of the finished product will also vary greatly depending on the knit or woven structure and fabric weight.
Selection and Handling Notes
When selecting fabric or yarn, in addition to the Nm value, check the material, twisting specifications such as single yarn or plied yarn, twist, fabric weight, and density in the specification sheet. When twisting multiple yarns together, the thickness of the final yarn changes, so it is important to avoid misreading the notation.
Metric count is an indicator of yarn thickness and does not directly indicate shrinkage or dimensional change due to washing. In particular, fabrics containing natural fibers should undergo washing tests and wetting before production samples are made, and the shrinkage rate, skewing, and puckering after sewing should be checked before deciding the pattern and sewing conditions.
Thin fabrics or high-density fabrics made with fine-count yarns may show needle holes, seam puckering, and sewing shrinkage more clearly. Verify in advance the sewing machine needle, sewing thread, thread tension, and stitch count suitable for the fabric, and adjust interfacing and seam finishing as necessary.
Differences from Similar Terms
Denier, tex, and decitex are constant-length units that express thickness by weight per a fixed length. In these units, the larger the number, the thicker the yarn, and the relationship between the number and thickness is the opposite of metric count.
Hemp count is also a constant-weight count, but the handling of the standard length differs from metric count. Also, count is a general term for yarn thickness, and in practice multiple count systems are used depending on the material, place of production, and application.
Frequently Asked Questions
Does a larger metric count mean a thicker yarn?
What do the 2 or 3 before Nm mean?
In twisting notation, the number may indicate how many yarns are twisted together. For example, in a 2-ply twist, combining two of the same single yarns makes the final yarn thicker. However, because the notation order can vary by commercial practice, check the single-yarn count and number of plies in the specification sheet.
Can fabric thickness or shrinkage be determined from metric count alone?
No. Fabric thickness is determined not only by yarn count, but also by structure, density, fabric weight, processing, and material. Shrinkage is also affected by the type of fiber, finishing, and washing conditions, so before mass production it is necessary to perform shrinkage tests and sewing tests on the fabric itself.
