Capacitor Energy Calculator Formula

Understand the math behind the capacitor energy calculator. Each variable explained with a worked example.

Formulas Used

Stored Energy

energy_j = 0.5 * cap_f * pow(voltage_v, 2)

Stored Energy (mJ)

energy_mj = 0.5 * cap_f * pow(voltage_v, 2) * 1000

Variables

VariableDescriptionDefault
capacitance_ufCapacitance(µF)1000
voltage_vVoltage(V)25
cap_fDerived value= capacitance_uf / 1000000calculated

How It Works

Capacitor Energy Storage

E = 0.5 x C x V^2

Energy scales with the square of voltage, so doubling voltage quadruples energy.

Worked Example

1000 uF capacitor at 25 V.

capacitance_uf = 1000voltage_v = 25
  1. 01C = 1000 uF = 0.001 F
  2. 02E = 0.5 x 0.001 x 25^2 = 0.5 x 0.001 x 625 = 0.3125 J

Ready to run the numbers?

Open Capacitor Energy Calculator