Enter the angular frequency in rad/s, the normal frequency in Hz, and the capacitance in farads to calculate the impedance of a capacitor.

Impedance Formula

The following formula can be used to calculate the impedance of a capacitor.


  • Where XC is reactance, which can be considered impedance
  • ω is the angular frequency in rad/s
  • f is the normal frequency in Hz
  • C is the capacitance in farads

As can be seen from the formula above, the impedance of a capacitor can be calculated using either the normal frequency or the angular frequency.

Impedance Definition

Impedance is the effective resistance of a circuit or component to an alternation current. This resistance arises from the effects of both ohmic resistance and reactance.

In an ideal resistor, the resistance of the resistor is exactly equal to the impedance. In an ideal capacitor, the impedance is equal to the magnitude of the reactance. It should be noted that impedance is represented by an expression of a real and imaginary component, while reactance is an ordinary number. In the case of an ideal capacitor, however, we are assuming the imaginary part of this expression to be 0, and so we can represent the impedance using the formula above.

How to calculate impedance

The following example is a step-by-step guide on how to calculate the impedance of an IDEAL capacitor.

  1. First, you must determine whether to use the angular frequency of the circuit or the normal frequency of the circuit. For this example, we will use the normal frequency and say it had a value of 200 Hz.
  2. The next step is to determine the capacitance of the circuit and or capacitor. For the example, we will assume that the capacitance is equal to 200 Farads.
  3. Finally, enter the information into the formula. 1 / 2 * pi * 200 * 200 = .00000398.
  4. Analyze the results and apply what’s been learned.


What is impedance?

Impedance is the effective resistance of a circuit or component to alternation current.

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impedance formula