Inductive Reactance

How to use this calculator

Enter the AC signal frequency and the inductance, and the inductive reactance X_L = 2π f L is computed instantly in the most readable unit. Reactance is the AC "opposition" an inductor presents — unlike a capacitor it rises with both frequency and inductance, so a large inductor at high frequency looks like a big impedance, while a small inductor at low frequency looks almost like a short circuit.

What the value means in a circuit

Because X_L depends on frequency, inductors pass low frequencies and block high ones — the heart of chokes, low-pass filters, RF suppression and the resonant frequency f = 1/(2π√(LC)) formed with a capacitor. It also carries a 90° phase shift (voltage leads current), which is used when building the complex impedance Z = R + jX_L and analysing power factor in AC and motor-drive circuits.