Unit of mass: kilogram (kg)
The kilogram is the unit of mass; it is equal to the mass of the international prototype of the kilogram.
The international prototype of the kilogram is an artefact made of platinum-iridium; a cylinder made of an alloy for which the mass fraction of platinum is 90 % and the mass fraction of iridium is 10 %. The protoptype is kept at the BIPM under the conditions specified by the 1st CGPM in 1889 when it sanctioned the prototype.
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