This study aimed to develop reduction factors for eccentrical ultimate bearing capacity of circular and square footings resting on geogrid-reinforced sand. The process has been simplified with presenting non-dimensional charts for the various load eccentricities, the number of reinforcement layers and footing shape, which can be used by practicing engineers directly. To establish and evaluate this approach a series experimental tests for circular and square shallow footings was considered. Regarding square footing, different ratios of load eccentricity were considered; one-way and two-way. The proposed approach for eccentrical loading in unreinforced and reinforced condition has been validated with Meyerhof’s Effective Width Concept, laboratory model tests and numerical reported data in the literature review. Also, this solution is verified using the results of field tests on actual full scale reinforced soil foundations to study scale effects. New method provides reasonable agreement of the ultimate bearing capacity. Also, the results of laboratory tests conducted by the authors show that the ultimate bearing capacity of circular footing decreases less with increment of load eccentricity in comparison with square footing in reinforced condition. Improvement Index investigated that contribution of reinforcement layers in enhancing the ultimate bearing capacity increases with the load eccentricity. This behaviour followed with the proposed model. Also, finite element method (FEM) in a three-dimensional space is performed for verifying the laboratory tests and studying the stress–strain behaviour of reinforcement layers.