Yarn fineness is an index used to measure the thickness of yarn. There are two calculation formulas commonly used in textile science: the calculation formula of fixed length system and the calculation formula of fixed weight system.

Fixed length system calculation formula

1. Tex (Tex) number - also known as "number", refers to the number of grams of weight of 1000 meters long yarn under the common fixed moisture return rate, it is a fixed length system unit, the larger the weight of yarn thicker, commonly used to represent yarn.

2. denier (D) - also known as "denier" or (Denier: denier), refers to the number of grams of weight of 9000 meters of yarn or fiber under the public moisture regain rate, it is also a fixed length system unit, the larger the gram weight of yarn or fiber, the thicker, commonly used to represent chemical fiber filament, silk, etc.

3. Ditex (dtex) - referred to as fen, symbol tex, refers to the number of grams of weight of 1000 meters long yarn under the common moisture recovery rate, dtex=dg/L*1000, where dg is the weight of yarn (or silk) (decigram), L is the length of yarn (or silk) (meters). It is a fixed length system unit, the larger the decigram weight, the thicker the yarn, and is commonly used to represent fiber yarns.

Calculation formula of fixed weight system

1. Imperial count (Ne) - at a common moisture return rate, a multiple of 840 yards of length of 1 pound of yarn, that is, 1 pound of yarn is exactly 840 yards long, which is 1 yarn, 1 pound of yarn length is 21×840 yards long, and the fineness of yarn is 21, which is written as 21s. The imperial count is fixed weight, so the larger the count, the finer the yarn. The imperial count is not the legal yarn fineness index in China today, but it is still widely used in enterprises, especially in the cotton textile industry.

2. Metric count (Nm) - under the common moisture recovery rate, the meter multiple of the length of 1 gram heavy yarn, that is, 1 gram heavy yarn is exactly 1 meter long, for 1 (male) yarn, 1 gram heavy yarn length is 200 meters long, and the fineness of yarn is 200 pieces. The metric count is also fixed weight, so the larger the count, the finer the yarn. Cotton textile and wool textile industry are used.

Fixed length system and fixed weight system unit conversion formula

The conversion formula of metric count (Nm) and Denier (D) : D=9000/Nm

The conversion formula of imperial count (S) and Denier (D) : D=5315/S

The conversion formula of dtex and tex is 1tex=10dtex

Tex and Denier (D) conversion formula: Tex=D/9

The conversion formula of Tex and imperial count (S) is: Tex=K/S

K value: pure cotton K=583.1; Pure chemical fiber K=590.5; Polyester cotton yarn K=587.6; Cotton adhesive yarn (75:25)K=584.8; Cotton yarn (50:50)K=587.0

The conversion formula of Tex and metric number (N) : Tex=1000/N

The conversion formula of dtex and Denier (D) is dtex=10D/9

The conversion formula between dtex and imperial count (S) is: dtex=10K/S

K value: pure cotton K=583.1; Pure chemical fiber K=590.5; Polyester cotton yarn K=587.6; Cotton adhesive yarn (75:25)K=584.8; Cotton yarn (50:50)K=587.0

Conversion formula between dtex and metric count (N) : dtex=10000/N

Reprinted: Dr. Seshang Fang Cloth