Reactance Calculator (Capacitive & Inductive)

Calculate capacitive reactance (Xc) and inductive reactance (Xl) at a frequency, the net reactance, and the resonance point.

Enter a frequency plus a capacitance and/or an inductance. SI prefixes accepted: 1k, 100n, 4m7.
Capacitive reactance X_c
Inductive reactance X_l
Net reactance (X_l − X_c)
Resonance (X_l = X_c)

Reactance

Reactance is the opposition a capacitor or inductor presents to alternating current, measured in ohms but varying with frequency. Capacitive reactancefalls as frequency rises; inductive reactance rises.

Capacitive: X_c = 1 / (2π·f·C)

Inductive: X_l = 2π·f·L

In a series LC circuit the net reactance is X_l − X_c: positive means the circuit looks inductive, negative means capacitive, and zero is resonance, where they cancel at f₀ = 1 / (2π·√(L·C)).

Related

Find the tuning point with theLC resonant frequency calculator, or combine parts first with thecapacitor andinductor series & parallelcalculators.