The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant hto be 6.626 070 15 x 10–34 when expressed in the unit J s, which is equal to kg m2 s–1, where the metre and the second are defined in terms of c and ΔνCs.
The Estonian National Laboratory for Mass realizes the scale of mass in the range from 1 mg to 50 kg using a group of 1 kg standard weights and highly accurate automated mass comparators. The 1 kg standard weights are calibrated by the International Bureau of Weights and Measures (BIPM) and the German National Metrology Institute (PTB).
The National Laboratory for Mass calibrates OIML Recommendation R 111-1 compliant weights in the accuracy range
E2 to F1 with an expanded measurement uncertainty of 2 μg to 15 mg.
Allar Pärn
allar.parn@metrosert.ee