ISO 31 (Quantities and units, International Organization for Standardization, 1992) is a superseded international standard concerning physical quantities, units of measurement, their interrelationships and their presentation. [1] . It was revised and replaced by ISO/IEC 80000. The standard comes in 14 parts:

ISO 31-0 is the introductory part of international standard ISO 31 on quantities and units. It provides guidelines for using physical quantities, quantity and unit symbols, and coherent unit systems, especially the SI.

International Standard IS0 31-1 was prepared by Technical Committee lSO/TC 12, Quantities, units, symbols, conversion factors. This second edition cancels and replaces the first edition (IS0 31-1 :1978). Th e major technical changes from the first edition are the following:

ISO/Guide 31:2015 is intended to help reference material (RM) producers in preparing clear and concise documentation to accompany an RM. It lists and explains mandatory, recommended and other categories of information to be considered in the preparation of product information sheets and RM certificates.

Gives general information about principles concerning physical quantities, equations, quantity and unit symbols, and coherent unit systems, especially the International System of Units, SI, including recommendations for printing symbols and numbers.

This part of IS0 31 gives general information about principles concerning physical quantities, equations, quantity and unit symbols, and coherent unit systems, especially the International System of Units, SI. The principles laid down in this part of IS0 31 are in-

ISO 31 （国际标准化组织 1992年制定的 质量 与 单位 标准）是一个被国际广泛认可的 物理量 和 量度 单位的样式指引。 全球的科学和教育文件中的公式都是参照这个标准列出的。 大多数国家的 数学 和 物理 教科书中的符号都依据ISO 31给出的建议书写。 该标准目前已被 ISO/IEC 80000 取代。 IEC 60027 是另一个质量与单位的国际标准。 ISO 31和IEC 60027分别由 国际标准化组织 和 国际电工委员会 制定。 由两个组织合作制定的 ISO/IEC 80000 国际单位制 中的量与等式也引 …

Gives name, symbol and definition for 21 quantities and units of space and time. Where appropriate, conversion factors are also given. Annex A includes units based on the foot, pound and second and some other units, Annex B other non-SI units given for information, especially regarding the conversion factor.

ISO 31-1 [1] is the part of international standard ISO 31 that defines names and symbols for quantities and units related to space and time. It was superseded in 2006 by ISO 80000-3 and again in 2019 by ISO 80000-3:2019.

ISO 31-11:1992 was the part of international standard ISO 31 that defines mathematical signs and symbols for use in physical sciences and technology. It was superseded in 2009 by ISO 80000-2:2009 and subsequently revised in 2019 as ISO-80000-2:2019 .