In this work, a detailed nonlinear model for the full dynamics of the F-16 aircraft is first developed and coded in MATLAB. This model includes the gravity model, variable atmospheric parameters, tabular aerodynamic functions, propulsion model, nonlinear control surface actuation models, and six degrees of freedom equations of motion. A numerical tool for computing all possible trim values, using the aforementioned model, is then developed. This tool can calculate the trim values at different operating points. In the developed algorithms, particle swarm optimization (PSO) method, which is a meta-heuristic method with a high convergence rate over a continuous search space, is used. Simulations around the calculated trim values are then made using the developed model. Simulation results confirm that the PSO based trim algorithm can find all the trim values with a high accuracy.