In this paper a set of equation known as Invariant Error Computation (IEC) is introduced that is used to examine directly the invariant performance properties of moment invariant techniques. The technique consists of a set of equations known as Total Percentage Min Absolute Error (TPMAE), Percentage Min Absolute Error 1 (PMAE1), Percentage Min Absolute Error 2 (PMAE2) and Percentage Absolute Error (PAE). These equations are utilized to measure the similarity between different feature vectors produced by the moment techniques studied. In order to evaluate the effectiveness of the IEC, we examine the invariant properties of three moment techniquesnamelyZernike Moment Invariant (ZMI), Legendre Moment Invariant (LMI), Krawtchouk Moment Invarian...