Capacitor Energy Storage Calculator

A capacitor's stored charge follows directly from the definition of capacitance, Q = C × V. The energy stored while charging it to that charge and voltage is E = ½ × C × V² (equivalently ½ × Q × V, or Q² ÷ (2 × C) — all three are algebraically the same result), derived by integrating the work done moving each small element of charge across the capacitor's growing voltage as it charges from empty to full.

Because energy scales with the square of voltage, doubling the voltage across a capacitor quadruples the energy it stores, while doubling capacitance at a fixed voltage only doubles it — voltage matters more than capacitance for how much energy is packed in.

Capacitance and voltage are entered directly with no metric/imperial toggle, since farads and volts are already unit-agnostic electrical quantities used worldwide, the same reasoning this site's Ohm's Law and Voltage Divider calculators already apply to their own electrical inputs.