From the results obtained for different geometric factors of the contactor (angle and inlet diameter) and for different operating conditions (particle size, stagnant bed height, and air velocity), the validity of a linear correlation based on the ratio between drag and gravitational forces is proven for the calculation of bed voidage in conical spouted beds when they operate in the transition between the regimes of a spouted bed and a jet-spouted bed. The parameters of this equation are calculated from the correlations previously proposed for the calculation of the bed voidage corresponding to these extreme regimes. The dependency on these parameters of the geometric factors and operating conditions has been determined.