We present the numerical package GravitinoPack that calculates processes involving the gravitino. GravitinoPack is written in Fortran77 and can be linked to Mathematica. The framework is the R-parity conserving Minimal Supersymmetric Standard Model, assuming that the gravitino is unstable or the Next to Lightest Supersymmetric Particle decays to gravitino. For calculating the squared amplitudes we use the packages FeynArts and FormCalc, with appropriate extensions to accommodate the gravitino with spin 3/2. Our code treats automatically the intermediate exchanged particles that are on their mass shell, using the narrow width approximation. This method considerably simplifies the complexity of the evaluation and stabilizes it numerically.