Why does voltage matter so much?
Stored energy is proportional to voltage squared, so doubling voltage quadruples ideal stored energy.
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Capacitor Energy Calculator — Joules, Charge & Voltage
Calculate stored capacitor energy and charge from capacitance and voltage, with common capacitance unit conversion.
Result
0.001 J
0.0002 C charge
0.00002 F at 10 V.
Formula and worked example
Energy E = ½CV²; charge Q = CV.
A 1,000 µF capacitor at 12 V stores 0.072 J and 0.012 C of charge.
Assumptions
- Capacitance and voltage are treated as ideal steady-state values.
- ESR, leakage, dielectric derating and discharge dynamics are not included in stored-energy math.
Last updated: 2026-09-16
Frequently asked questions
Does this predict discharge time?
No. Discharge time depends on the connected resistance/current profile and capacitor behavior.