We compute electrostatic field induced deformations of cantilevered finite-length metallic carbon nanotubes using an energy minimization method based on a charge-dipole moment interaction potential combined with an empirical many-body potential. The influence of field strength, field direction, and tube geometry on the electrostatic deflection is investigated for both single- and double-walled tubes. These results could apply to nanoelectromechanical devices based on cantilevered carbon nanotubes.