This standard contains formulas and tables which shall be applied to the calculation for the denomination of yarn count in the used yarn count systems.*This standard does not apply for sewing threads, for which exist different systems of denomination (label numbers), which are accepted between deliverers and customers.*In the tables 1 and 2 the common systems of denomination with their reference quantities and their formulas for calculation into tex and Nm are complied.*According to the law for units in the field of metrology only the application of the yarn counts systems tex and Nm are admitted.*In the future only the tex system which was agreed by ISO shall be applied. The fineness of yarns (linear density) of fibers and yarns expressed as quotient from the weight in a legal unit of the mass and the lenght in km shall be denominated.