Diffusion coefficients for cosmic ray propagation in the interplanetary magnetic field are obtained for particles of energies typically observed by ground-based neutron monitors. The estimates are made in the context of present quasi-linear and nonlinear theories. Recent observations of the interplanetary magnetic field fluctuations are employed. It is found that the diffusion coefficients derived from the theoretical models generally differ by less than 50%. These differences are less than experimental uncertainties arising from variations in the relevant solar wind observables, where the observables are obtained over scale sizes of the order of a few cosmic ray mean free paths.