Resonant Frequency Calculator

This resonant frequency calculator employs the capacitance (C) and inductance (L) values of an LC circuit (also known as a resonant circuit, tank circuit, or tuned circuit) to determine its resonant frequency (f).

You can use the calculator in three simple steps:

  1. Input any two parameters for a resonant circuit.
  2. Select the units of measurement you wish to use.
  3. Click "Calculate" and the resonant frequency calculator will calculate the third missing parameter.
LC Resonant Frequency Calculator


In the field of electronics, an LC circuit is employed to either generate signals at a particular frequency or select one signal from a more complex signal at a particular frequency. LC circuits play a fundamental role in the operation of many electronic devices, including radio equipment, and are utilized in circuits such as filters, oscillators, tuners, and frequency mixers.

LC circuits consist of two connected electronic components: the inductor (L) and the capacitor (C).

When the L and C are placed in parallel or series, they have a resonant frequency. This resonant frequency is represented by the following equation:

f = 1 / (2π √L C)

Where: f is the resonant frequency in hertz (Hz), L is the inductance in henries (H), C is the capacitance in farads (F), π is the constant (3.141592654…)

An example of a resonant frequency calculation

Let's say we wish to determine the resonant frequency of an LC circuit that has an inductor of 3 mH, and a capacitor of 3 µF.

Solution: The resonant frequency (f) of the circuit is as follows:

f = 1 / (2 × 3.141592654 × √ (3×10^(-3) × 3×10^(-6)))

f = 1677.64 Hz ≈ 1.678 KHz.


This resonant frequency calculator employs the following formulas:

f = 1 / (2π √L C)   Resonant Frequency [Hz]

L = 1 / (4π2 f2 C)   Inductance [H]

C = 1 / (4π2 f2 L)   Capacitance [F]

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