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Capacitor Energy Calculator

Calculate the energy stored in a charged capacitor from its capacitance and the voltage across it, using E = ½ × C × V².

Stored energy
0.0072J
In millijoules
7.200 mJ

Formula: E = ½ × C × V²

About Capacitor Energy Calculator

Capacitor Energy Calculator is a free online calculator that gives you an instant, accurate result as you type. Calculate the energy stored in a charged capacitor from its capacitance and the voltage across it, using E = ½ × C × V².

The calculation uses the standard formula E = ½ × C × V² and updates live with every change to the inputs. Everything runs client-side in your browser — fast, private, and free to use as often as you like.

Camera flashes work by slowly charging a capacitor and then dumping its stored energy through the flash tube in a few milliseconds.

Frequently Asked Questions

Is Capacitor Energy Calculator free to use?

Yes. Capacitor Energy Calculator is completely free, with no sign-up, no downloads, and no usage limits. You can use it as many times as you like on any device with a web browser.

How accurate is this calculator?

The calculator applies the standard formula (E = ½ × C × V²) with full floating-point precision and rounds only the displayed result. For most practical purposes the results are exact.