comparison between the national prototype of the kilogram and stainless steel mass standards

In 2013, the National Prototype of the Kilogram (NPK) No. 2 belonging to Romania, together with stainless steel kilogram standard Ni 81, received an updated mass value from BIPM. Therefore, the first task after their receiving from BIPM was to perform comparisons between NPK and reference kilograms stainless steel standards. In the paper are described mass standards, weighing scheme used for comparisons, calculations of mass and associated uncertainties, as the mass change for all weights involved. It is also presented a comparison between Romanian CMC(s) and other countries for this important stage of dissemination of mass unit.