We validate the quantitative analysis of Ronchigrams for wavefront sensing through detailed numerical simulations. Analysis of the experimental Ronchigrams provides the wavefront aberrations, the F/# of the beam and the distance of the Ronchi ruling from the paraxial focus. These retrieved parameters are used to numerically simulate the Ronchigrams with excellent agreement. This favorable comparison validates the accuracy of the wavefront recovery and provides a tool to examine the accuracy and robustness of this wavefront measurement technique.