Field-reversed configurations are compact toroids confined solely by poloidal fields. Recent experiments and numerical calculations have demonstrated that they can be formed infield-reversed theta pinches on time scales longer than the radial Alfvén time. This considerably eases the technological requirements for large devices, and permits reasonable formation schemes to be developed for future experiments. Scaling laws are developed for both flux trapping and heating effectiveness as a function of the formation time scale and poloidal flux level.