Enter Values
Formula
Xc = 1 ÷ (2πfC)
If voltage is entered, ideal RMS current is I = V ÷ Xc.
Example
A 100 µF capacitor at 60 Hz has approximately 26.53 Ω of capacitive reactance.
How Frequency Affects Xc
Capacitive reactance decreases as frequency or capacitance increases. A capacitor therefore blocks steady DC after charging but can pass changing AC current.
Real capacitors also have ESR, inductance, voltage limits, ripple-current limits, and frequency-dependent behavior.