To provide a calibration method and system for calibrating a meter devoid of a process connection part.

The system 200 includes a connection adapter 216, where the system is operable for calibrating both linear and nonlinear meters with multiple flow rates, and is suitable for use with different standard references including both gravimetric and master standard references. The process connection adapter includes: a system mating part in the form of a flange, sanitary or some other type of sealing connection for piping for ensuring a leak-free seal between the process connection adapter and a calibration system; a meter mating part for ensuring a leak-free seal between the process connection adapter and a part of the meter to be attached to the process connection part; and an intermediate part for fluidly connecting the system mating part to the meter mating part.