Mass and pressure

Unit of mass: kilogram (kg)

​The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant h to be 6.626 070 15 × 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 ∆νCs.

Information on the practical realisation of the definition of the kilogram can be found in the ​Mise en pratique for the definition of the kilogram in the SI.


Unit of pressure: pascal (Pa)

Pressure is the amount of force applied perpendicular to the surface of an object per unit area and the for it is p  (or P).

The SI unit for pressure is the pascal (Pa), equal to one newton per square metre (N/m2, or kg·m−1·s−2). Pascal is a so-called coherent derived unit in the SI with a special name and symbol.


Calibration services for mass and pressure