Abstract: An automatic online analyzer validation and calibration system receives operating parameter input signals from sensors, receives a measured value of a selected process variable from a physical analyzer, determines a difference between the measured value and an inferred value of the selected process variable determined by a controller based on the operating parameter input signals using an inferential analyzer; and if the difference between the measured value and the inferred value exceeds a threshold, initiates a recalibration of the physical analyzer or recalibration of the inferential analyzer. In one example, the automatic online analyzer validation and calibration is used in a gas dehydration system to validate and calibrate a physical moisture analyzer.