Inductors in Parallel Calculator

Ideal uncoupled inductors connected in parallel share the same voltage. Their equivalent inductance follows a reciprocal rule: one divided by equivalent inductance equals the sum of one divided by each branch inductance. For three branches, the calculator evaluates all three reciprocals and then inverts their sum. The result is always smaller than the smallest individual inductance, just as parallel resistance is smaller than the smallest branch resistance. After finding equivalent inductance, the calculator uses XL = 2 pi f L to determine the network's inductive reactance at the selected frequency. Dividing RMS voltage by reactance gives ideal RMS source current. Each branch has the same applied voltage but carries a current inversely proportional to its own inductance. The displayed total current is the sum of those in-phase ideal branch currents. At a fixed voltage, adding another parallel inductor reduces equivalent inductance and reactance, so source current increases. Parallel inductors appear in current-sharing power stages, filter networks, and designs that combine available component values. The reciprocal relationship applies when the magnetic fields do not interact. If coils share a core or sit close enough for significant mutual coupling, their dot orientation and coupling coefficient change the result. In that situation, a coupled-inductor model is required and the simple independent-branch formula can be misleading. Real inductors also include winding resistance, core loss, and parasitic capacitance. Those properties make each branch impedance complex and frequency dependent. Current may not divide according to inductance alone, especially at high frequency or near self-resonance. Component tolerances can also cause unequal current sharing even when nominal inductance values match. Check saturation current and thermal ratings for every branch, because one coil may reach its limit before the total network appears overloaded. This calculator is intended for steady-state sinusoidal analysis of three ideal, uncoupled inductors. Enter inductance in henries, frequency in hertz, and applied RMS voltage in volts. A zero voltage is accepted and correctly produces zero current. Use peak rather than RMS values only if all related quantities use the same convention. For practical hardware, compare the ideal estimate with impedance curves and current ratings from the relevant data sheets.