Linear Yarn Density (Denier vs Tex / ISO 1144)
Direct Answer
Linear yarn density is the scientific measure of fiber fineness and yarn mass per unit length governed by ISO 1144 and ASTM D861. Denier defines mass in grams per 9,000 meters of yarn (common in synthetic nylon/polyester and Cordura), while Tex represents the international SI standard of grams per 1,000 meters, converted via the constant ratio 1 Tex = 9 Denier.
Source: ISO 1144:2016 / ASTM D861-07 (Linear Density of Textile Fibres)
Specs
| Governing Standards | ISO 1144 / ASTM D861 / ASTM D1907 (Tex System) |
| Denier Definition (den / D) | Mass in grams per 9,000 meters of filament yarn (1D = 0.111 mg/m) |
| Tex Definition (tex) | Mass in grams per 1,000 meters of yarn (1 tex = 1.000 mg/m) |
| Decitex Definition (dtex) | Mass in grams per 10,000 meters of yarn (1 dtex = 0.900 denier) |
| Mathematical Conversion | Tex = Denier ÷ 9 | Denier = Tex × 9 |
| Ultralight Apparel Fibers | 10D to 30D (sheer hosiery, down jackets, parachute ripstop) |
| Heavy-Duty Technical Yarns | 500D (standard Cordura backpack) | 1000D–1680D (ballistic nylon luggage) |
Denier vs Tex Mathematical Mechanics
Both Denier and Tex are direct yarn numbering systems: a higher numerical value indicates a thicker, heavier yarn with greater tensile strength: $$\text{Denier (D)} = \frac{\text{Mass in grams}}{\text{Length in meters}} \times 9,000$$ $$\text{Tex} = \frac{\text{Mass in grams}}{\text{Length in meters}} \times 1,000$$
Because $9,000 \div 1,000 = 9$, converting between systems is exact:
- A $500\text{D}$ Cordura nylon yarn equals $55.5\text{ Tex}$ ($500 \div 9$).
- A $1000\text{D}$ Ballistic nylon yarn equals $111.1\text{ Tex}$ ($1000 \div 9$).
Microfiber Classification (Under 1.0 Denier)
By international textile definition, a fiber is officially classified as a Microfiber if its linear density is less than $1.0\text{ Denier}$ ($<0.11\text{ Tex}$). Natural silk filaments measure approximately $1.0\text{ to } 1.3\text{ Denier}$, while high-tech polyester/polyamide microfiber cleaning cloths utilize split fibers as fine as $0.1\text{ to } 0.3\text{ Denier}$ ($100\times$ finer than human hair), creating immense surface area for capillary dirt trapping.