The present invention refers no a plant for filling bottles or containers with continuous calibration and to a continuous calibration method of such a plant. The calibration method (100) is characterized in that it comprises the steps consisting of collecting (110) at least one set of data relating to filling and/or closing parameters of containers or bottles (16) treated through the same tap or filling valve (15) of the filling plant (10) and/or through the same closing and/or capping head (14) of the filling plant (10); based on the data collected, calculating (120) statistical data associated with the tap or filling valve (15) and/or with the closing and/or capping head (14); updating (130) the statistical data based on new data collected and monitoring the progression thereof; in the case of a variation of the statistical data over time, adjusting the tap or filling valve (15) and/or the closing and/or capping head (14) associated with the statistical data so as to compensate for the variation.