  For superconducting coils with many turns, it is widely believed that the
magnetic field from magnetization currents is negligible compared to the one
generated by the whole coil. This article shows that this is not true for coils
with a considerably large number of turns (up to thousands). We introduce a
method to accurately calculate the AC loss in coils with virtually any number
of turns that takes the magnetization currents into account. The current
density and AC loss is analyzed for two windings made of coated conductor
consisting of 32 pancake coils totaling 768 and 6400 turns, respectively.
