International Standard ISO 31 (Quantities and units, International Organization for Standardization, 1992) is the most widely respected style guide for the use of units of measurement, and formulas involving them, in scientific and educational documents worldwide. In most countries, the notations used in maths and science textbooks, at schools and universities, follow exactly the guidelines given by ISO 31.

The standard comes in 14 parts:

ISO 31-0: General principles

ISO 31-1: Space and time

ISO 31-2: Periodic and related phenomena

ISO 31-3: Mechanics

ISO 31-4: Heat

ISO 31-5: Electricity and magnetism

ISO 31-6: Light and related electromagnetic radiations

ISO 31-7: Acoustics

ISO 31-8: Physical chemistry and molecular physics

ISO 31-9: Atomic and nuclear physics

ISO 31-10: Nuclear reactions and ionizing radiations

ISO 31-11: Mathematical signs and symbols for use in the physical sciences and technology

ISO 31-12: Characteristic numbers

ISO 31-13: Solid state physics

See also

• SI - also note the external links section: as opposed to ISO, BIPM supplies free information on quantities and units (in particular the latter)

References

ISO standards are available for purchase online. All parts of ISO 31 along with ISO 1000 are available in book form as

ISO Standards Handbook: Quantities and units. 3rd ed., International Organization for Standardization, Geneva, 1993, 345 p., ISBN 92-67-10185-4, 182.00 CHF. http://www.iso.ch/iso/en/prods-services/otherpubs/Handbooks.PublicationList?CLASSIFICATION=HANDBOOKS