Scales are initially calibrated at the factory they are made with their local traceable weights of that country, this can be anywhere in the world, so it's important to test the equipment prior to use due to gravitational influences of the balance being used in a different place to the original calibration.
Weighing equipment can lose its accuracy for a variety of reasons such as shock loading (i.e. portable scales used in different locations, such as care homes, hospitals, vans etc.) can cause a change in the reading, or may have "fell off the bench" and no one reported it. Our engineers test, calibrate, adjust, all scales purchased through this website to ensure trouble free weighing.
Budget scales may need calibration more often dependant on
usage and storage criteria, and if used for critical control of your process
may warrant purchasing a more repeatable product i.e we wouldn't reccomend kitchen scales for factory use, many of which have no spirit level or means of calibration adjustment.
Annual calibration of scales provide traceability on the condition of your scales, and helps identify errors or operational issues such as damaged cables, broken screen or safety issues , and that the scales are within the original manufacturers tolerances.