Skip to main content
ÚNMZ - logo

Issue of a revision of the Units of Measurement Directive



On 24 July 2019, the Commission Directive (EU) was published in the Official Journal of the EU 2019/1258adapting to technical progress the Annex to Council Directive 80/181/EEC as regards the definitions of the SI base units.

New definitions of the SI base units were adopted at the 26th CGPM meeting in 2018. These new definitions are based on the new principle of fixing the numerical values of the defining constants and are effective from 20 May 2019. The new definitions are intended to improve the long-term stability and plausibility of the SI base units, as well as the accuracy and clarity of measurements, and further reflect the latest developments in measurement science and standards. Directive 80/181/EEC on units of measurement has also been revised for these reasons. The revision of the Directive will enter into force on 13 August 2019 and will subsequently be transposed into Czech law.