Two systems of measurement are used:
1. mass so-called linear weight - the ratio of the weight of the yarn to its length
units: tex = weight [ g ] of a 1,000 piece of yarn [ m ]
dtex = weight [ g ] of the 10,000 length of yarn [ m ]
den = weight [ g ] of the 9,000 length [ m ] yarn
2. long - the ratio of the length of the yarn to its weight
units: metric numbering Nm = [ m ] of a single yarn for [ g ]
English numbering Ne = [ m ] of a single yarn for 0.59 [ g ]