Magnetic field dependent exciton binding energy and the interband emission energy with the geometrical confinement in a Cd 0 2 Zn 0 8 Te/ZnTe quantum dot are computed using a single band effective mass approximation with the variational method. The exciton Landé g factor as functions of geometrical confinement and the magnetic field strength is investigated. The hole g-factor due to the geometrical confinement not only in the z-direction but also in lateral direction is computed taking into account the effective mass of hole, in plane and z-direction. It is found that the effects of spatial confinement and the magnetic field strength lead the reduction of Landé g factor and it increases with the Zn alloy content in the barrier material. Our results show that the effect of magnetic field is more pronounced for larger dot radius and the geometrical dependence of Landé g factor reveals that it decreases as the Zn alloy content and the dot radii increase. It approaches the values of Landé g factor of ZnTe (barrier material) for smaller dot radius.