Using our capacitor energy calculator, you can find how much energy and charge a charged capacitor can hold.

If you're wondering, "How does a capacitor store energy?" 💡 we will give you a brief explanation of the topic as we introduce:

  • The energy in a capacitor equation; and
  • The charge on a capacitor equation.

By pairing these expressions, you can find how much charge is stored in a capacitor and learn how to find the energy stored in a capacitor.

What is a capacitor, and how does a capacitor store energy?

A capacitor is a device that stores electrical charge. The simplest capacitor is the parallel plates capacitor, which holds two opposite charges that create a uniform electric field between the plates.

Therefore, the energy in a capacitor comes from the potential difference between the charges on its plates.

🙋 If you're already familiar with these concepts, feel free to start working with the capacitor energy calculator!

How to find energy stored in a capacitor. Energy in a capacitor equation

You can easily find the energy stored in a capacitor with the following equation:

E=CV22E = \frac{CV^{2}}{2}


  • EE is the stored energy in joules.
  • CC is the capacitor's capacitance in farad; and
  • VV is the potential difference between the capacitor plates in volts.

Replace each parameter, and the result will be the energy the capacitor can hold.

If you don't want to bother with these calculations, our capacitor energy calculator can quickly find this value for you 😉

Charge on a capacitor equation

Another output of the capacitor energy calculator is the capacitor's charge QQ. We can find the charge stored within the capacitor with this expression:


where again:

  • CC is the capacitor's capacitance;
  • VV is the potential difference across the capacitor; and
  • QQ is the charge within the capacitor, expressed in coulombs.
Luciano Mino
Capacity (C)
Voltage (V)
Stored charge (Q)
Stored energy (E)
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