Accurate de Haas-van Alphen data for Cu due to Joseph et al. are analyzed using Mueller's expansion technique. Cubic-harmonic analysis is extended to treat certain multiply connected geometries, thereby obtaining Fermi radii for Cu. These radii are then used in conjunction with the results of Burdick's augmented-plane-wave calculation and Mueller's interpolation scheme to determine the Fermi energy EF and the position of the d bands relative to the conduction bands (EF-L3). It is found that the value of EF-L3 so determined agrees with the optical data. The belly and neck cyclotron masses were calculated and compared with the experimentally obtained masses. The electron-phonon enhancement of the experimental masses (~25%) was found to be almost independent of the location of the extremal orbit on the Fermi surface.