LC Resonant Frequency Calculator

The resonant frequency is f = 1 / (2 pi sqrt(L C)), with L in henries and C in farads. Enter 1 mH and 100 nF, which is 1e-3 H and 1e-7 F, and the result is 15.9155 kHz.

At the resonant frequency the inductive reactance and the capacitive reactance are equal in size and cancel. A parallel LC tank shows peak impedance there, while a series LC circuit shows minimum impedance and passes the most current.

Angular frequency omega is 2 pi times the ordinary frequency, measured in radians per second, and it also equals 1 / sqrt(L C) directly. Engineers use it in reactance and phase equations, so both forms are returned for convenience.

Inductance takes henries, millihenries or microhenries, and capacitance takes farads, microfarads, nanofarads or picofarads. The tool converts your choice to base SI units before applying the formula, so mixing scales is safe.

Yes. The ideal resonant frequency is identical for series and parallel LC circuits; only the impedance behaviour at resonance differs. This calculator gives that shared ideal figure.

Raising either the inductance or the capacitance lowers the frequency. Because of the square root, multiplying L or C by four halves the resonant frequency, and multiplying by nine cuts it to a third.

No. It models an ideal lossless LC pair, so it ignores winding resistance, capacitor leakage, stray capacitance and the loading of a real circuit. Those shift and broaden the peak slightly, so treat the result as the ideal center frequency.

The engine rounds the frequency and angular frequency to six decimal places, and the display shows up to four decimals in the chosen unit. That is far finer than the tolerance of typical inductors and capacitors, which are often 5 to 20 percent.

Yes. The calculation runs entirely in your browser with no network request, so the values you type are never uploaded and the page works offline once loaded.