A calibration system and methods for flow metering technologies integrates a known primary reference standard (e.g., a gravimetric scale), configured to determine a mass of calibration fluid, in parallel with surrogate secondary masters (e.g., Coriolis effect flowmeters) connected via an adjustable flowpath having a closed loop mode, including a meter bank, a pump and a measuring section, and an open loop mode, including a reservoir, the meter bank, the pump, the measuring section and the primary reference standard, which enables calibration duality and redundant meter under test confirmation of calibration factors. The disclosed systems and methods enable life cycle assurance of the primary reference standard and the secondary masters' standard reliability and reproducibility over time and, as a redundant system, enable calibration of multiple flow metering technologies, such as, for example, volumetric, mass, density, viscosity and Reynolds number-reliant technologies, in one homogenous system.