Convert Worsted Count to Kilotex (Nw to ktex)

Formula

ktex = 0.8858118711724 ÷ Nw

Derivation from SI units:

• Nw = number of 560-yard hanks per pound, so tex = 885.8119 ÷ Nw
• 1 ktex = 1 g per metre = 1000 tex = 10⁻³ kg/m (exact)
• Solving for ktex: ktex = 0.8858118711724 ÷ Nw (a higher Nw means a lower ktex)

Both units are defined exactly, so the factor is exact. Worsted Count definition: worsted count; Kilotex definition: kilotex.

Worked examples

1. A reading of 24 Nw converts to 0.03690882797 ktex.
   0.8858118712 ÷ 24 = 0.03690882797 ktex
2. A value of 48 Nw is 0.01845441398 ktex.
   0.8858118712 ÷ 48 = 0.01845441398 ktex

Where it's used

Worsted Count are used for worsted wool and acrylic yarns, while kilotex appear in card and draw-frame sliver (about 3–5 ktex). Both measure yarn count (linear density of yarns and fibres), but one system is the inverse of the other, so a fixed constant is divided by the value.

Worsted Count to other yarn count units

Frequently asked questions

Sources

• ASTM D2260, Standard Tables of Conversion Factors and Equivalent Yarn Numbers Measured in Various Numbering Systems, ASTM International , Worsted count.
• Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "yard" and "pound".
• ISO 1144, Textiles — Universal system for designating linear density (Tex System), International Organization for Standardization , Tex system.

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.