Actual Structures are subjected to variable amplitude loading as opposed to a monotone. Many models have been proposed to study these effects analytically. The proposed study focuses on developing an algorithm, and a corresponding framework in MATLAB for two of these models, i.e. the NASGRO equation for constant amplitude loading, and Generalized-Willenborg for overload effects. The overload influence is modeled by keeping track of changes in the crack-tip plastic-zone. Two cases are studied with the algorithm, and the results indicate that the presence of overload tends to retard crack growth, thereby validating our algorithm with literature findings.