Denier to Tex

How Many Tex in a Denier?

One denier equals 1/9 tex, or equivalently, 1 tex = 9 denier. To convert denier to tex, divide the denier value by 9. Denier and tex are both measures of linear density — the mass per unit length of a fiber or yarn — but they use different reference lengths. Denier measures grams per 9,000 meters of fiber, while tex measures grams per 1,000 meters. Denier is the older unit, deeply entrenched in the hosiery, lingerie, and synthetic fiber industries. Tex is the ISO standard unit (ISO 1144) adopted for international textile trade. When buying nylon stockings, you encounter denier: sheer stockings are 10-15 denier, semi-opaque are 30-40 denier, and opaque tights are 60-100+ denier. Technical textiles, industrial yarns, and international trade documents use tex. The conversion is simple division or multiplication by 9, making it one of the easiest textile conversions to perform. Fiber manufacturers like Dupont, Toray, and Hyosung publish specifications in both units, but regional preferences persist: denier dominates in the US and Asia for consumer products, while tex is preferred in European technical specifications.

How to Convert Denier to Tex

1. Start with the fiber linear density in denier.
2. Divide the denier value by 9 to get tex.
3. For example, 70 denier / 9 = 7.78 tex.
4. The conversion is exact: 1 tex = 9 denier, by definition.
5. Common conversions: 15 denier = 1.67 tex, 40 denier = 4.44 tex, 100 denier = 11.11 tex, 210 denier = 23.33 tex, 1000 denier = 111.11 tex.

Real-World Examples

History of Denier and Tex

Denier originated in the French silk trade. The word comes from the Roman coin denarius and was used as a unit of weight in France (1 denier = approximately 1.2 grams). Silk traders measured fiber fineness by weighing a standard 9,000-meter length of silk thread. The number of deniers it weighed became the fiber's denier rating. This system worked well for silk, which was the primary fine fiber for centuries. When synthetic fibers (nylon, polyester, acrylic) emerged in the 1930s-1950s, the denier system was naturally extended to them. Meanwhile, the International Organization for Standardization introduced tex in 1960 (ISO 1144) as a rationalized metric alternative: grams per 1,000 meters (rather than grams per 9,000 meters). The factor of 9 between denier and tex reflects the factor of 9 between 9,000 and 1,000 meters. Despite ISO standardization, denier persists in consumer-facing products because decades of marketing have made terms like "70 denier tights" and "1000 denier nylon" familiar to consumers.

Common Mistakes to Avoid

• Confusing denier and tex with GSM. Denier and tex measure linear density (mass per length of fiber), while GSM measures areal density (mass per area of fabric). You cannot convert denier to GSM directly without knowing the fabric construction (weave type, thread count, etc.).
• Multiplying by 9 instead of dividing. Denier numbers are always larger than tex numbers for the same fiber. If your tex result is larger than the denier input, you went the wrong way.
• Forgetting that denier describes a single fiber or yarn, not a fabric. A "70 denier" stocking uses 70 denier yarn, but the fabric's overall weight depends on how densely that yarn is knitted.
• Mixing per-filament denier with total yarn denier. A multifilament yarn can have a much larger total denier than each individual filament, so check whether the specification is talking about the bundle or the single filament.

Frequently Asked Questions