A system for measuring directional characteristics of a downhole tool includes: at least one bending moment (BM) measurement device disposed at a downhole component, the at least one BM measurement device configured to generate bending moment data at at least one depth in the borehole, the bending moment data including a bending vector of the downhole tool, a bending moment representing an amplitude of the bending vector, and a bending tool face (BTF) angle representing an orientation of the bending vector; and a processor in operable communication with the BM measurement device and configured to receive bending moment data from the BM measurement device, calculate a dogleg severity (DLS) from the bending moment and a well tool face (WTF) angle from the BTF angle, and calculate at least one of a change in inclination and a change in azimuth based on the DLS and the WTF angle.