Tex
Tex: grams per kilometre of fiber or yarn
Tex is the metric world's answer to a simple question: how heavy is this fiber or yarn for its length? Defined as the mass in grams per 1000 metres, tex is a direct measure of linear density — the higher the tex, the heavier and coarser the yarn. It is more likely to be used in Canada and Continental Europe, while denier remains more common in the United States and the United Kingdom, and it sits alongside traditional units such as worsted count, cotton count and yield. This page defines tex, its sub-units such as decitex and millitex, and its place among the fiber measurement systems.
The linear density of a fiber is commonly measured in units of denier or tex. Traditional units include worsted count, cotton count and yield. Tex is more likely to be used in Canada and Continental Europe, while denier remains more common in the United States and United Kingdom. The International System of Units uses kilogram per metre for linear densities; in some contexts, the tex unit is used instead.
Tex is a unit of measure for the linear mass density of fibers, yarns and thread and is defined as the mass in grams per 1000 meters.
The metre, or meter (American spelling), is the base unit of length in the International System of Units (SI). The SI unit symbol is m. The metre is defined as the distance travelled by light in a specific fraction (1/299 792 458) of a second. The imperial inch is defined as 0.0254 metres (2.54 centimetres or 25.4 millimetres). One metre is about 3 3⁄8 inches longer than a yard, i.e. about 39 3⁄8 inches.
The unit code is "tex". The most commonly used unit is actually the decitex (abbreviated dtex), which is the mass in grams per 10,000 meters.
When measuring objects that consist of multiple fibers, the term "filament tex" is sometimes used, referring to the mass in grams per 1000 meters of a single filament.
Tex is used for measuring fiber size in many products, including
cigarette filters, optical cable, yarn and fabric.
Measurements most commonly use the International System of Units (SI)
as a comparison framework. The system defines seven fundamental units:
kilogram, metre, candela, second, ampere, kelvin, and mole.
Direct Systems Make Comparison Easy
Tex belongs to the direct family of yarn numbering: fix the length, weigh it, and the number rises with coarseness. That direction makes tex intuitive across materials — a 20 tex cotton and a 20 tex polyester have the same mass per kilometre even though their fiber diameters differ with density — and it makes arithmetic friendly: double the tex and you have doubled the mass of yarn in the same length. The older indirect counts work the other way, rising as yarns get finer, which is why mills converting between systems keep formulas close at hand and why this section gives each system its own page.
Tex and Its Relatives
Denier, tex's closest relative, weighs 9000 metres instead of 1000, so a yarn's denier is nine times its tex; decitex (dtex), weighing 10,000 metres, is ten times the tex and is the unit filament producers most often print. All three are the same idea at different scales, chosen so that typical fibers land in comfortable number ranges: millitex for single fine filaments, decitex and tex for yarns, kilotex for heavy rovings and tows. The yield page in this section covers the inverse idea — length per unit weight — which is how the same property is quoted when buyers think in coverage rather than mass.
Common Questions
What is tex in textiles?
Tex is a unit of linear mass density for fibers, yarns and thread, defined as the mass in grams per 1000 metres of material.
Where is tex most commonly used?
Tex is more likely to be used in Canada and Continental Europe; denier remains more common in the United States and United Kingdom.
How does tex relate to denier?
Both are direct linear-density units: denier is grams per 9000 metres and tex is grams per 1000 metres, so a yarn's denier number is nine times its tex number.