The rocket equation in a form that accounts for the force of gravity or rocket weight was included in the latest version of FinSim to determine drag-free burnout velocity and drag-free burnout altitude for single stage rockets launched from the surface of the Earth. This new feature was implemented on the Fin Geometry for Aeroelastic Analysis screen, where burnout velocity and burnout altitude are plotted with the red Vb designation on the flutter velocity verses altitude plot when using the NACA 4197 Flutter Velocity Tool. This new feature in FinSim makes it possible to immediately compare predicted flutter velocity to rocket equation burnout velocity and burnout altitude for any single stage rocket using FinSim. However, the question by several FinSim users was “how accurate is the rocket equation for predicting burnout velocity and burnout altitude”. This simple question was the genesis for this paper which attempts to quantify the accuracy of the rocket equation compared to the finite difference method and TR-10 model rocket altitude prediction method for computing burnout velocity and burnout altitude. One not so surprising result is the accuracy of the rocket equation verses altitude increases as the dimensions, mass and rocket motor performance including thrust and burn time is increased. This analysis helps to quantify the accuracy of the rocket equation for burnout velocity and burnout altitude verses mass fraction using FinSim’s new NACA 4197 Flutter Velocity Tool.