AbstractRadiated seismic energy is expressed in terms of slip velocities by using an overdamped dynamics approximation. This formulation is used to estimate the radiated energy from earthquake finite‐fault models. A correction term is found to show that the approximation underestimates the radiated energy as defined by the full dynamics. The accuracy of the overdamped dynamics solution depends on the rupture history. Two dislocational earthquake models illustrate the dependence of the correction term on the rupture speed and slipping area size. The radiated seismic energies estimated from the finite‐fault models and from seismic waves are compared for real‐world earthquakes. The results are consistent in most cases. Discrepancies between two estimates suggest that both the finite‐fault models and energy estimations from teleseismic data should be revised.