On the 26th General Conference on Weights and Measures organized by the International Bureau of Weights and Measures (BIPM) on November 16, 2018 in Versailles in France, the representatives from 54 countries voted unanimously for the International System of units (SI) revision, whose application will start on May 20, 2019. New definitions of the kilogram, the ampere, the kelvin and the mole were adopted.
The redefined SI is now on based on fundamental nature constants. The kilogram is determined on basis of the Plank constant (h), the ampere is based on the elementary charge (e), the kelvin is based on the Boltzmann constant (k) and the mole is based on the Avogadro constant (NA).