Accurately estimating cutting tool life under specific cutting conditions is a critical challenge in manufacturing systems like flexible manufacturing systems (FMS). The cutting force on the tool can be estimated using the traditional formula, which yields an average value. However, the impact effect that occurs when the cutting tool hits the workpiece during the initial cutting operation—which is approximately 1.1–1.5 times the normal cutting force—significantly shortens the tool’s actual life and causes it to fail too soon. For machinery like shapers, force dynamometers are frequently unavailable. Therefore, it becomes crucial to estimate the cutting force indirectly. In this study, we estimate the cutting tool life while taking into account the impact that response measurements during machining have on it. The dynamic reaction is often insufficient in structural evaluation tests; a description of the input force may be necessary. Determining the frequency response function (FRF) matrix, measuring the structural responses, and computing the dynamic forces using the least squares scheme are the most recommended methods for solving this issue. This method’s forces are subject to inaccuracy. The force prediction process uses the acceleration response as input. To ascertain the impact force amplitude, the frequency domain is used to create the impact force history prediction algorithm. This creates the force estimate issue, which is subsequently solved to find the impact force’s amplitude. This force can be used to estimate the cutting tool’s life through iterative testing.