We derive a general formula for the gravitational free energy of Euclidean supersymmetric solutions to D=4, N=2 gauged supergravity coupled to vector multiplet matter. This allows one to compute the free energy without solving any supergravity equations, just assuming the solutions exist. As well as recovering some known results in the literature with ease, we also present new supergravity results that match with holographically dual field theory computations.