Capacitance Calculator

Created by Luciano Mino
Last updated: Jul 04, 2022

With our capacitance calculator, you will be able to easily calculate the capacitance of a parallel plate capacitor or find the distance between the plates.

In this short article below, we will briefly describe:

  • What is and how to calculate capacitance;
  • The capacitance formula for a parallel plate capacitor; and
  • What the units of capacitance are.

Continue reading to learn more!

Capacitance definition

The capacitance of an object is its capacity to store electric charge. It is a ratio between the charge stored and the potential difference across two conductors in its interior.

The higher the capacitance, the greater the amount of charge that can be stored using the same potential difference.

Let's now see how to find a capacitor's capacitance and what the capacitance units are.

How to calculate capacitance

In general, capacitance is defined as:

C=QVC = \frac{Q}{V}

where:

  • CC is the capacitance in farads (F). A capacitor holding 1 coulomb of charge with a potential difference of 1 volt has a capacitance of 1 farad.
  • QQ is the electric charge contained inside the capacitor.
  • VV is the potential difference.

For a parallel plate capacitor, we can replace these variables with others that are easier to work with. This way, the capacitance formula becomes:

C=εAsC = \frac{ε A}{s}

where:

  • AA is the area of the plates in m². Our area converter can help you with this step, or you can switch units using the capacitance calculator's built-in unit converter.
  • ss is the distance between the plates in m.
  • εε is the dielectric permittivity of the material between the plates in farads per meter. Permittivity of vacuum is 8.854 pFm8.854\ \frac{\text{pF}}{\text{m}}.

💡 You can type in any value for permittivity using the advanced-mode in the capacitance calculator!

Example

Let's say we have a 12 pF12\ \text{pF} parallel plate capacitor with 10 cm²10\ \text{cm²} plates, and we want to find how close these plates are. How do we do it?

First, we should rearrange the capacitance formula to find our missing parameter:

s=εACs = \frac{ε A}{C}

Now, we can replace our values in this formula (using the permittivity of vacuum, 8.854 pFm8.854\ \frac{\text{pF}}{\text{m}}) to get the distance between the capacitor plates.

This results in:

s0.74 mms \simeq 0.74\ \text{mm}

🙋 Remember to convert everything to m, , F, and F/m before replacing the values in the equation.

Luciano Mino
C = εA/s
Area (A)
in²
Separation distance (s)
in
Capacitance (C)
pF
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