This e-learning course teaches basic principles of calibration for various mechanical instruments, including vacuum gauges, pressure gauges, weighing balances, weights, and tachometers. Participants gain knowledge on equipment selection, metrological traceability, and calibration agency selection. They also understand ISO/IEC 17025:2017 measurement uncertainty requirements, theory of uncertainty, selection of factors, calculation, instrument measurement relevance, technical requirements, and calibration methods.