We present a consistent dynamical nucleation theory based on density functional theory. By considering the properties of stable droplets in closed volumes, the height and shape of the barrier to nucleation are calculated. Contributions from fluctuations in the center of mass of the nucleating cluster are taken into account. Forward and backward rates for cluster dynamics are obtained, and nucleation rates are then evaluated under steady-state conditions. We test the quantitative effects of several shortcuts to calculating nucleation rates. The predictions of the full theory presented here show very modest changes from those of the simpler nonclassical theory proposed earlier by Oxtoby and co-workers.