Inductance is indirectly proportional to the square of the number of turns, the permeability, and the cross-sectional area of the core.

Some factors that affect the inductance of a coil include:

1. The inductance is proportional to the square of the number of turns;
2. The inductance increases directly as the permeability of the core material increases;
3. The inductance increases directly as the cross-sectional area increases; and
4. The inductance decreases as its length increases.