This document is an excerpt from the EUR-Lex website
Directive 80/181/EEC on the approximation of EU countries’ laws relating to units of measurement
It lists and defines the legal units that must be used to express quantities in the European Union (EU). It specifies that the metric units of measurement / International System of Units (SI units)* are applicable in the EU.
Council Directive 80/181/EEC has been amended several times. The last one, introduced by Commission Directive (EU) 2019/1258 for the purpose of its adaptation to technical progress, amends the annex as regards the definitions of SI base units.
SI units are mandatory in the EU for economic, public-health, public-safety and administrative purposes.
SI units originated from international resolutions adopted by the General Conference on Weights and Measures (CGPM) to which all EU countries adhere.
The directive lists and defines the permitted and mandatory units of measurement in a series of annexes, including the following.
The definitions of the units are based on natural constants, allowing for accurate measurements even on a very small scale. As such, they can be used not only in everyday life, but also for purposes requiring very high precision, like scientific research or advanced technological applications.
Exemptions: The directive does not affect the use of units in air and sea transport and rail traffic as laid down in international agreements binding the EU or EU countries.
Derogations are only applicable in Ireland and in limited circumstances:
Supplementary indications
The directive also allows the use of supplementary indications (those of quantity expressed in units of measurement not contained in the directive). They cannot, however, be used by themselves; they can only accompany the SI units listed and defined in the directive and the SI units have to predominate.
It has applied since 1 October 1981 and had to become law in the EU countries by 1 July 1981.
For more information, see:
Council Directive 80/181/EEC of 20 December 1979 on the approximation of the laws of the Member States relating to units of measurement and on the repeal of Directive 71/354/EEC (OJ L 39, 15.2.1980, pp. 40-50)
Successive amendments to Directive 80/181/EEC have been incorporated into the original text. This consolidated version is of documentary value only.
last update 03.02.2021