🔋 Capacitor Calculator
Calculate the charge and energy stored in a capacitor, plus its capacitive reactance at a given AC frequency.
What a capacitor stores
A capacitor stores electrical energy in an electric field between two conductive plates. The amount of charge it holds depends on its capacitance and the voltage across it, and in AC circuits a capacitor also presents an impedance called capacitive reactance that depends on frequency.
How this calculator works
Charge is calculated using Q = C × V, where C is capacitance in farads and V is the voltage across the capacitor. Stored energy uses E = ½ × C × V². For AC applications, capacitive reactance is calculated as Xc = 1 / (2π × f × C), where f is the signal frequency; reactance decreases as frequency or capacitance increases, which is why capacitors pass high frequencies more easily than low ones.
This tool is for general electronics education and estimation. For circuit design, verify capacitor voltage and current ratings are appropriate for your application.