Parallel inductance is simple to calculate once you know how to do it. This skill may help. To get the total inductance of two coils in series, add the inductance together. Think of it as just adding more turns to the coil. Parallel inductance calculated by this skill is a little trickier. The formula is: Parallel inductance = (L1 + L2) / (L1 + L2). You can use this skill to calculate parallel inductance for two coils. I don't like dividing by zero so avoid coils with an inductance of zero.