Abstract: The values of mechanical, potential, and kinetic energy were found for each planet. The orbit of the planet was treated as an ellipse, producing two values- an aphelion and perihelion value. The data from “Equations for Planetary Orbits” was used as the “measured” values and the data from NASA was used as the accepted values. The percent error between the two values was between 0.1% and 0.9%. An adjustment to the equations in “Equations for Planetary Orbits” showed a decrease in this error.