The balance is the instrument that allows you to weigh, or determine the mass, of a sample.
You need to keep in mind that weight and mass are two different physical quantities.
The main difference is that the mass corresponds to the amount of matter from which an object is composed. The weight (or force weight), is the value of the force with which the mass is attracted to the centre of the earth.
Because gravity varies in the various angles of the planet, the difference between weight and mass strength becomes relevant in the balance calibration with high precision.
For this reason, it is advisable to calibrate immediately after installation at a given location.