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Measurement units redefined to enable more accurate measurement

Ministry of Economic Affairs and Employment
Publication date 11.6.2020 14.09 | Published in English on 15.6.2020 at 17.34
News item

Finnish legislation has been changed with regard to the definitions of measurement units. This change was made following a redefinition of the base units in the international measurement system. The base units include second, metre and kilogram. The new definitions will enable even more accurate measurement, and lay the foundation for new innovations and technologies.

The international system of units, or SI system (Système International d’Unités) is based on seven base units: second (time), metre (length), kilogram (mass), ampere (electric current), kelvin (thermodynamic temperature), mole (amount of substance) and candela (luminous intensity). These agreed measurement units are the basis for international trade, among other things.

In the international November 2018 revision of the SI, the definitions of SI base units were changed. The base units remained unchanged, but they were redefined in terms of constants of nature. Their new definitions are based on fixed numerical values.  The definitions of all base units of the SI are now uniformly expressed using the explicit-constant formulation; this is the biggest change in the SI system since its introduction in 1960. The redefinition is expected to improve the long-term stability and reliability of base units as well as the accuracy and clarity of measurements.

Amendment to enter into force in Finland on 13 June

The internationally agreed amendment was incorporated into EU legislation in summer 2019. In Finland, provisions on compliance with the international measurement system are laid down in the Act on Measurement Units and Measurement Standard System. Under this Act, provisions on the definitions of SI base units are laid down in the Government Decree on Measurement Units.

On 11 June 2020, the Government issued a Decree on amending the Government Decree on Measurement Units. The amendment to the Decree will implement the amendment to EU legislation. The amendment entered into force on 13 June 2020.

Following the redefinition of SI base units, the teaching materials of educational institutions will need to be updated.


Anne Hyartt, Chief Specialist, Ministry of Economic Affairs and Employment, tel. +358 295 047 175

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