A two-dimensional fast Fourier transform technique is proposed for accelerating the computation of scattering characteristics of features on surfaces by using the discrete-dipole approximation. The two-dimensional fast Fourier transform reduces the CPU execution time dependence on the number of dipoles N from O(N2) to O(N log N). The capabilities and flexibility of a discrete-dipole code implementing the technique are demonstrated with scattering results from circuit features on surfaces.